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What is the main challenge in creating a chemical male contraceptive?

What is the main challenge in creating a chemical male contraceptive?


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More than 50 years after hormonal contraception for women was invented, a contraceptive pill for males is still not available. With the obvious major biological differences in mind, why does it appear more difficult to create a chemical contraceptive for males? What are the main challenges that must be overcome to create a viable, reliable and marketable contraceptive pill for men?


I am going to summarize a few reasons for both why contraception is "easier" for women, and for why it is "harder" for men. They are both biological and sociological.

Easier for women

The female cycle is more complicated

The female cycle leading to ovulation is regulated by several hormones that interact. As such, it is easier to disturb.

The system is so sensitive that even the slightest alteration in any of these factors can disrupt its fluidity and lead to anovulation

(Anovulation = a cycle where no ovulation occurs) Source: Anovulation: Background, Pathophysiology, Epidemiology

Even in young women, this occurs naturally.

Estimates of chronic anovulation rates range from 6-15% of women during the reproductive years

Female bodies l already have a "built-in mechanism for contraception

As ovulation needs to be suppressed during pregnancy, there is already a mechanism in place by which this can happen.

Women are more affected by pregnancy

Since women are more affected by pregnancy and childbirth, the risk they feel they have when they don't use contraception or use it incorrectly is larger.

Contraceptives for women have more than one use

More than half of pill users, 58%, rely on the method at least in part for purposes other than pregnancy prevention. Thirty-one percent use it for cramps or menstrual pain, 28% for menstrual regulation, 14% for acne, 4% for endometriosis, and 11% for other unspecified reasons.

Beyond Birth Control: The Overlooked Benefits of Oral Contraceptive Pills

Harder in men

It only takes one

While the saying "it only takes one sperm" is probably an exaggeration, it carries a certain truth - you really need to shut down the production of sperm or the risk of a pregnancy is too high. Both the pill and the various IUD options have set a high bar for what's considered an acceptable risk.

Side effects and effectiveness

While hormonal contraception for women already has a multitude of side effects, often unrelated to the reproductive system, this is certainly not easier in men. The most prohibiting side effect encountered so far is impotence - not much use in taking birth control to have sex without risk of pregnancy when doing so leads to no sex at all.

Progestins have been used in multiple small studies of men for suppression of spermatogenesis and testosterone production. Progestins used alone result in significant side effects such as loss of libido and erectile dysfunction.

Update on Male Hormonal Contraception: Is the Vasectomy in Jeopardy?

(Decreased libido is also a side effect in female hormonal contraception, though. The reasons why it's seen as more acceptable there are probably sociological)

That review is a good overview on what has been tried until 2010. Many solutions failed because of side effects or because they didn't work well enough.

On testosterone:

Of note, this international study revealed that 91% of Asian and 60% of Caucasian patients became azoospermic, suggesting an ethnic difference in endocrine response

Testosterone proved to be rather good in other doses and combinations, but is not that easy to handle because it requires injections and can't be taken orally.

Testosterone alone has side effects, including acne and oily skin, mood changes, increased hemoglobin and hematocrit, weight gain, decrease in testicular volume, sleep apnea, gynecomastia and possible effects on cholesterol. There are no long-term data with testosterone use and normal men regarding prostate symptoms, growth or cancer. In an era of fear of using medications on relatively healthy individuals, acceptability of routine use may be a major concern, given recent data on medical treatment of menopause with estrogen/progestin therapy. In addition, anabolic steroids are a controlled substance and regulation of this industry is very strict at this time. Abuse of these drugs could easily become prevalent with its widespread use and availability for contraception.

On cryproterone acetate:

Doses ranging from 25 to 100 mg per day have suppressed spermatogenesis, but side effects have precluded subsequent studies.

And so on…

The market factor

A side effect of the contraceptive options for women being so well-accepted, women often feeling responsible for contraception and also using hormonal contraception anyway, for reasons unrelated to pregnancy, is that the market for male contraception is not that easy and pharmaceutical companies have been pulling away from it. Especially in light of the research difficulties.

Although Bayer, Wyeth and Organon were once active in research and development of a male method, all three discontinued their programs between 2005 and 2008 although the industry continues to actively pursue programs for hormonal contraception and hormonal-replacement therapy for women. In withdrawing support, company representatives cited corporate changes in direction and the perception that safety standards demanded by regulatory bodies would require such extensive evidence as to make further research financially infeasible

Current challenges in male contraceptive research

This is not to say that there really is no market. As you mentioned in the comments, at least in questionnaires, many men say they would use male hormonal contraception and many women say they would like their partners to use it. See, for example, Market size for male contraception (plus the following pages of that paper)

But you asked about the challenges ;-)

I think it's also interesting to note that the search for hormonal contraception started for both men and women. It's just that the "solution" was found for women first and then got popular really fast.


Recent Developments in Male Contraception

Unplanned pregnancies are an ongoing global burden, posing health and economic risks for women, children, and families. Advances in male contraception have been historically stymied by concerning failure rates, problematic side effects, and perceived market limitations. However, increased interest in reliable and reversible options for male contraception have resulted in resurgent efforts to introduce novel contraceptives for men. Hormonal male contraception relies on exogenous androgens and progestogens that suppress gonadotropin production, thereby suppressing testicular testosterone and sperm production. In many men, effective suppression of spermatogenesis can be achieved by androgen-progestin combination therapy. Small-scale contraceptive efficacy studies in couples have demonstrated effectiveness and reversibility with male hormonal methods, but side effects related to mood, sexual desire and cholesterol remain concerning. A number of novel androgens have reached clinical testing as potential contraceptive agents many of these have both androgenic and progestogenic action in a single, modified steroid, thereby holding promise as single-agent contraceptives. Currently, these novel steroids hold promise as both a “male pill” and long-acting injections. Among non-hormonal methods, studies of reversible vaso-occlusive methods (polymers that block transport of sperm through the vas deferens) are ongoing, but reliable reversibility and long-term safety in men have not been established. Proteins involved in sperm maturation and motility are attractive targets, but to date both specificity and biologic redundancy have been challenges for drug development. In this review, we aim to summarize landmark studies on male contraception, highlight the most recent advances and future development in this important field of public health and medicine.


Why We Can’t Have the Male Pill

The trouble began, as it so often does, with a bottle of Chivas Regal.

Back in the 1950s, scientists at Sterling Drug, a now-defunct pharmaceutical company, synthesized a class of chemicals that made male rats temporarily infertile. They thought they might be onto something big: the first-ever birth control pill𠅏or men. After identifying several promising compounds, including one known as WIN 18,446, a trio of researchers began testing them on a ready population, inmates at the Oregon State Penitentiary.

The results were astonishing. Within 12 weeks, the inmates’ sperm counts had plummeted. When the men stopped taking the drugs, sperm production returned to normal. Better yet, they experienced few side effects.

Then one of the participants drank some contraband Scotch and became unusually, violently ill. He confessed his transgression to the researchers, and follow-up studies confirmed his account: WIN 18,446 didn’t mix well with booze. Men who combined the two reported heart palpitations, sweating, nausea, and vomiting. The research was quietly abandoned.

For years, headlines have promised an imminent breakthrough in male contraception. Time and again, these efforts have fallen short. Last October, for instance, researchers reported that a hormone cocktail they𠆝 been testing curbed sperm production and prevented pregnancies. But they𠆝 had to halt the study early because men were reporting troubling side effects, including mood changes and depression.

“The joke in the field is that the male contraceptive has been five years away for the last 40 years,” says John Amory, a research physician at the University of Washington School of Medicine who has been working on the challenge for two decades. A new form of male birth control would be a public-health triumph and could snag a significant piece of the contraceptive market—which is expected to surpass $33 billion by 2023, according to research firm Global Market Insights Inc.—or possibly expand it further. In a 2002 German survey of 9,000 men in nine countries, including Brazil, France, Germany, Mexico, and the U.S., more than 55 percent of the respondents said they𠆝 be willing to use a new form of male birth control. A later study by Johns Hopkins University estimated that the demand could yield 44 million customers in those nine countries alone. And yet major pharmaceutical companies have mostly abandoned the chase.

That has left a scrappy tribe of scientists to fill the void. They’ve dreamed up a vast array of ideas, from the conventional—hormone gels, implants, and injections designed to temporarily suppress sperm production—to the decidedly unorthodox. (Men, prepare to have lasers beamed at your testes.)

For his part, Amory is trying to resurrect the drug that showed so much potential in prisoners. But turning WIN 18,446 into a contraceptive has, like other such quests, proven difficult𠅊s stubbornly elusive as discovering alien life or harnessing energy from nuclear fusion. “When I was in high school, I thought I was going to become a physicist and work on developing fusion,” Amory says. “Then I started working on this, and now I wonder what we’re going to have first: workable fusion or a male pill?”

When it comes to preventing pregnancy, women have a multitude of choices. There are diaphragms and sponges cervical caps and female condoms spermicidal gels, foams, films, creams, and suppositories hormone-delivery systems involving pills, implants, injections, patches, vaginal rings, and IUDs. These options are far from perfect𠅊nd they remain inaccessible and unaffordable for many women𠅋ut at least they exist.

Men have only two choices: condoms, which have a real-world failure rate of about 18 percent, and vasectomy, a surgical procedure that’s often permanent. A new contraceptive could give men more control over their reproductive futures, alleviate a burden that’s overwhelmingly borne by women, and reduce the rate of unintended pregnancies, which is about 40 percent worldwide, according to the nonprofit Guttmacher Institute. Women have sometimes argued—not unconvincingly—that the lack of a male pill reflects a double standard, but the scientific and regulatory challenges involved in creating a viable male contraceptive are vexing on their own.

After the U.S. Food and Drug Administration approved the first female birth control pill, which used a mixture of hormones to suppress ovulation, in 1960, researchers explored taking a hormone-based approach to men. Clinical trials in the ensuing decades showed that dosing men with testosterone or combinations of testosterone and progestin temporarily inhibited sperm production, but that the strategy had drawbacks. Testosterone is rapidly cleared from the body when taken orally, so a hormonal contraceptive for men would likely have to be delivered via injection, implant, or topical gel, rather than as a pill. What’s more, the hormones don’t work in all men, and because they don’t only affect the gonads, they can, as with the female pill, cause nasty side effects that have nothing to do with fertility.

Research into hormonal solutions continues, but the challenges have prompted some investigators to seek drugs that target sperm more directly. Scientists at the University of Kansas and the University of Minnesota are studying a compound called H2-gamendazole, which prevents sperm from maturing properly, while Eppin Pharma Inc., a small North Carolina company, is developing a drug that would stop sperm from swimming by binding to a protein on the surface of the cells.

And then there’s Amory, who happened upon WIN 18,446 by accident. After arriving at the University of Washington in 1997, he began a practice that soon proved paradoxical. As a clinician, he often treated infertile men who desperately wanted children, while as a researcher he sought to develop a hormone cocktail that would prevent men from becoming fathers. Then, in the fall of 2006, he came across a paragraph about the Oregon prison experiments in a profile of two pioneering fertility scientists.

“Spermatogenesis is a pretty formidable foe”

“It’s a fascinating story,” he says one rainy March morning in his office at the university’s labyrinthine health sciences building. Amory is a 50-year-old former rower and Eagle Scout, with the lanky build and cheerful, wholesome demeanor to match. He’s also an unabashed history buff and enthusiastic storyteller, and he calls up a carefully curated series of graphs to help him narrate the saga of WIN 18,446.

Initially, he says, the Sterling Drug scientists created the compound to treat parasitic infections. But when they tested it in rats, they noticed that the animals became infertile. “Then they stopped the drug, and the rats regained their fertility,” he says. “So they’re like, ‘Hey, maybe this could be a male contraceptive.’ This was before there was a pill for women.” Of course, rodents don’t drink, so it wasn’t until men started taking WIN 18,446 that researchers discovered it interacted dangerously with booze.

WIN’s side effects sounded familiar to Amory. In his clinical practice, he𠆝 occasionally prescribed Antabuse (disulfiram) to patients who struggled with alcohol addiction. The drug blocks a form of the enzyme acetaldehyde dehydrogenase (ALDH), which helps the body metabolize alcohol drinking while taking disulfiram leads to an extremely unpleasant, and occasionally fatal, constellation of hangover-like symptoms. But ALDH also plays a role in converting vitamin A to retinoic acid, which is required for sperm production. The pieces clicked into place: Amory realized that WIN 18,446 might inhibit ALDH, which would explain why it caused sperm counts to drop and why men taking it had adverse reactions to alcohol.

He tested his hypothesis in rabbits, dosing them with a WIN-laced banana-crème-flavored syrup. “Rabbits are brilliant, because their sperm counts are very similar to humans. They’re mammals just like humans, and you can train them to ejaculate into an artificial vagina,” he says, cuing up a video on his computer. “This is me making an artificial vagina.” (The faux orifice, it turns out, can be assembled from an ultrasound-probe cover and a thermos filled with water heated to about 100F, the approximate internal temperature of a female rabbit.)

After four weeks, the retinoic acid levels in the rabbits’ testes plummeted sperm production soon followed. “You can see what happened to their sperm counts,” Amory says, whistling as he traces a plunging graph line with his finger. “They go right down to zero. And then we stop the drug, and they come right back up.” The results suggested he𠆝 been right: WIN seemed to hobble sperm production by disrupting the synthesis of retinoic acid.

He concluded that WIN represented an elegant strategy for male contraception—it just needed to be better targeted. There are almost 20 different forms of ALDH the liver relies primarily on ALDH2 to metabolize alcohol, while the testes use ALDH1A2 to make retinoic acid. WIN disrupted both forms of the enzyme what they needed was a drug that blocked only ALDH1A2.

To help him tweak WIN, he turned to Alex Goldstein, a bespectacled, redheaded chemist who has become his collaborator and co-investigator. Over two years, Goldstein made about 100 versions of the compound, but none was selective enough. “So we went to plan B,” he says. With the help of a drug-screening robot, their team tested 55,000 additional chemical compounds, identifying about 300 that inhibited ALDH1A2. A leading contender soon emerged, with preliminary experiments suggesting it was more specific than WIN, and more potent.

Last year they put the compound, called CM-121, to the test, giving 10 mice daily doses for five weeks, measuring the animals’ retinoic acid levels, and counting the sperm in their testes. The results were disappointing. Within five hours of each dose, retinoic acid levels did indeed drop—then quickly returned to normal. Sperm production continued apace.

Fudge, Amory thought. (“I have two small boys, so I try not to swear,” he says.) He𠆝 really thought it would work. But he understands the field too well to call it his biggest setback. “Oh, gosh,” he says, sighing, “it’s all setbacks.”

𠇎verybody in the male birth control area is an underdog”

Drug development is an inherently difficult enterprise. Only 10 percent of the drugs that enter Phase I trials—the studies in which scientists evaluate dosing and basic safety in humans𠅎ver make it to pharmacy shelves, and it can easily cost hundreds of millions of dollars to bring a drug to market. Male contraception is a particular challenge. Contraceptives have to be extraordinarily reliable. Many drugs would be considered successes if they worked half the time, but few people would use birth control that failed so frequently.

Then there are the basic facts of reproductive biology. Most healthy women of reproductive age release one egg per month and stop ovulating when they’re pregnant they can suppress ovulation by taking hormones that mimic pregnancy, which is essentially what the pill does. But there’s no natural off switch for sperm production men make sperm from puberty until death. “Spermatogenesis is a pretty formidable foe,” Amory says. “Your body has evolved over eons to make a lot of sperm. In fact, most men make a thousand sperm every second.”

If researchers do find a promising drug, they’ll also need to persuade regulators to approve it. No one’s quite sure what that will take. Male contraceptive drugs represent an entirely new product category, and the FDA hasn’t yet laid out clear guidelines for them. Will regulators measure a male contraceptive drug against the female pill or simply compare it to the male-directed approaches now available? Will they want a male pill to be as effective as a vasectomy or simply more reliable than a condom? “Nobody really knows, because nobody’s gotten to that point,” says Zahed Subhan, chief executive officer of Eppin Pharma, the North Carolina company that’s testing a drug that aims to interfere with sperm movement.

There’s reason to believe it will prove tougher to win approval for the first male pill than it was for the female one. Research and regulatory standards have evolved considerably in the past 60 years—the Oregon prisoner tests likely wouldn’t pass muster today, nor would some early trials for the first female pill. (In one crucial study performed with low-income women in Puerto Rico, participants weren’t fully informed of the potential risks, and their reports of side effects were largely dismissed.) Some scientists have also speculated that the original formulation of the female pill, which contained much higher doses of hormones than current products do, wouldn’t be approved today.

Moreover, while female contraceptives aren’t without dangers, pregnancy entails serious health risks. This means regulators charged with making a risk-benefit calculation may conclude in some cases that unplanned pregnancies pose a greater hazard to women than the side effects of a new birth control product would. The female pill also has some noncontraceptive health benefits. The first birth control pill, Enovid, initially won FDA approval in 1957 to treat menstrual disorders it wasn’t approved as a contraceptive until three years later.

That men don’t bear the medical risks of pregnancy may change the calculus for regulators assessing a male contraceptive. So might the fact that men, with their long reproductive lifespans, could find themselves using birth control for decades longer than women typically take the pill. Unless researchers manage to find a contraceptive with real health benefits for men, regulators will probably have a low tolerance for side effects. 𠇊 male contraceptive solution just has to be squeaky clean,” Subhan says.

If a drug were approved and serious side effects popped up, pharmaceutical companies could face costly lawsuits. Litigation is always a risk for drugmakers, but medications designed to be taken by young, otherwise healthy patients for long periods of time, especially those affecting the reproductive system, could be particular targets. Women have filed, and sometimes won, high-profile lawsuits over female contraceptives, alleging that certain drugs and devices have caused a variety of serious injuries—including blood clots, uterine damage, birth defects, miscarriages, and infertility—or that contraceptive failures have left them with unwanted pregnancies.

“They were saying, ‘Well, this is really cool. It sounds great, but can my husband get it?’ ”

The scale and spread of the challenges may explain why pharmaceutical companies that once had active research programs had dropped them by about a decade ago. “The drug company funding has kind of dried up,” says Amory, who previously received financing from Organon BioSciences, Schering, and Bayer. “It seemed to some that they decided that the risk-benefit wasn’t favorable.” Although surveys show that men are interested in male contraception, because they don’t get pregnant they may be less motivated to take on the attendant hassles and risks. It’s also not clear if a new male contraceptive would expand the contraceptives market or cannibalize it. Companies profiting from existing solutions might be reluctant to invest in competing products.

Scientists at universities, nonprofits, and startups aren’t scaring so easily. 𠇎verybody in the male birth control area is an underdog,” Goldstein says. Amory and Goldstein’s work on WIN had been funded by the National Institutes of Health, but their grant—$1.5 million over five years—ran out at the end of June, and they don’t have more money lined up yet. Even an identical grant wouldn’t be nearly enough to develop an FDA-approved drug ready for widespread use. Their plan is to find a better, more potent candidate, assemble evidence that it’s safe and effective, and approach pharmaceutical companies about a partnership.

But that will take time. “Science is tough that way,” Amory says. “Most things don’t work.”

Some entrepreneurs say the path forward requires wholly rethinking male birth control.

“What is a male contraceptive?” asks Kevin Eisenfrats, the 24-year-old co-founder and CEO of Contraline Inc., a startup based in Charlottesville, Va. “Is it a drug, or is it a medical device?” Just inside the front door of the company’s two-story brick building, not far from the University of Virginia, a custom mural𠅊 silhouette of a man and woman walking into the sunset—is splashed across a side wall. A bowl of Contraline-branded, sperm-shaped foam stress balls sits on the reception counter.

Eisenfrats, who has long eyelashes and a spray of freckles on his nose, takes a seat at a cluttered conference table and delivers his elevator pitch. “What we’re developing is a nonsurgical and reversible alternative to a vasectomy,” he says. Contraline has created a hydrogel, called Echo-V, that can be injected into the vas deferens, the thin tube that transports sperm from the testes to the urethra. Upon injection, the gel solidifies, blocking the flow of sperm but allowing other fluid to pass through. Ideally, he says, when a man is ready to have children, a doctor would dissolve the gel.

The idea isn’t novel. It’s inspired by a technique known as reversible inhibition of sperm under guidance (Risug), invented in India in the 1970s. The Parsemus Foundation, a nonprofit based in Berkeley, Calif., is developing a similar product, called Vasalgel. But while Risug requires doctors to make a small opening in the skin of the scrotum to access the vas deferens, Contraline has invented a procedure, which it has dubbed “vasintomy,” that allows doctors to implant the gel nonsurgically, injecting it directly through the skin using an ultrasound to guide its placement. “No scalpels or sutures required,” Eisenfrats says. “It’s maybe a three-minute overall procedure.”

He hatched the idea while he was a senior at the University of Virginia School of Engineering & Applied Science and initially planned to market Echo-V to pet owners as an alternative to neutering. The veterinarians he reached out to were enthusiastic about the idea—just not for their animal patients. “They were saying, ‘Well, this is really cool. It sounds great, but can my husband get it?’ ” he says with a laugh.

Because Echo-V qualifies as a medical device, Contraline may have an advantage over rivals working on a male pill. The FDA typically requires more and larger clinical trials for drugs than it does for devices it takes 12 years, on average, to bring a new drug to market, compared with three to seven years for a new medical device. The expense therefore tends to be much higher for drugs.

Contraline, which was launched in March 2015, hasn’t had trouble attracting investors, raising $700,000 in a preliminary seed round last year, followed this spring by a second seed round of $2.3 million led by Peter Thiel’s Founders Fund. (𠇊t Contraline, we only do seeds,” Eisenfrats jokes.)

Other organizations are also exploring alternative funding models and research concepts. The Parsemus Foundation solicits tax-deductible donations from the public and accepts payment in bitcoin. Last year the foundation, which has 52,000 people on its mailing list, suggested supporters each donate 𠇊n hour’s wages” to raise the $127,000 it needed to manufacture the gel for its first clinical trial. (The campaign closed with $85,000, and a trial is planned for 2018.) The Male Contraception Initiative, a nonprofit, has also run a crowdfunding campaign for researchers.

As for more radical scientific approaches, British researchers are working on a so-called clean-sheets pill that would stop men from ejaculating during orgasm. A German company has devised an implantable valve�vertised to be “small as a gummy bear” and �% vegan”—that would let men turn the flow of sperm on and off with the flick of an actual switch. And a Chinese team has piloted an approach that involves injecting gold nanoparticles into the testes and heating them with an infrared laser. None are likely to be commercially available soon—indeed, they haven’t yet been tested in humans, though Clemens Bimek, the German who developed the spermatic duct valve, reportedly had several prototypes implanted in his scrotum.

Contraline’s research team is racing to be one of the first to market with a viable solution. The company is tinkering with the gel’s formulation, assessing its efficacy and biocompatibility, designing an injection device, and refining the injection and reversal procedures. Eisenfrats says he plans to begin a preclinical trial in large animals next year, begin human trials in 2019, and earn FDA approval in 2021.

It’s an ambitious timeline. The developers of Risug and Vasalgel have been at it longer than Eisenfrats, and they’ve both faced setbacks and delays—hopes for Risug have been high for the past 15 years. Still, Eisenfrats is confident Contraline can pull it off. “Some people think it’s a little aggressive, but I wouldn’t say anyone has ever called bullshit on it,” he says. “It’s doable. The pathway we’re taking makes sense.”

On the back wall of Contraline’s first-floor laboratory, two posters depict artifacts from the strange and slightly horrifying history of contraception: a condom made from animal intestines, a screw-like device designed to be inserted into the uterus, a box of 𠇊nti-baby” tablets, a lemon. “This is what was in the past,” Eisenfrats says, pointing. 𠇊nd this,” he adds, turning and gesturing at his gleaming new lab, still being stocked with equipment, “is where we’re going.”

One afternoon this spring, Amory and six members of his research team gather for a lab meeting in a small, windowless room down the hall from his office. Goldstein, the chemist, clicks through slides crammed with chemical names and structures. He’s been synthesizing new compounds, looking for one more potent than CM-121, the former lead contender. Of the hundreds he’s made so far, several seem strongly and selectively to inhibit ALDH1A2. “That’s good,” Amory says. “That’s a bunch of good inhibitors.”

He has stopped predicting when his team might be ready to start human trials, let alone have a pill ready for sale. And he’s fine with the possibility that they won’t be the first to break through—that Contraline or someone else might beat them to market. “I don’t feel like we’re in a race or that it’s a competition,” he says. Rather, he hopes that someday a wide variety of options will be available to men, including his two sons.

“My dream is to send them off to college with a five-year, reversible, male contraceptive implant,” Amory jokes. But his boys seem to be growing up faster than the field is moving. “I have an eighth-grader now, so I’m not sure I’m going to make that deadline.”


Contents

Chance of pregnancy during first year of use [23] [24]
Method Typical use Perfect use
No birth control 85% 85%
Combination pill 9% 0.3%
Progestin-only pill 13% 1.1%
Sterilization (female) 0.5% 0.5%
Sterilization (male) 0.15% 0.1%
Condom (female) 21% 5%
Condom (male) 18% 2%
Copper IUD 0.8% 0.6%
Hormonal IUD 0.2% 0.2%
Patch 9% 0.3%
Vaginal ring 9% 0.3%
MPA shot 6% 0.2%
Implant 0.05% 0.05%
Diaphragm and spermicide 12% 6%
Fertility awareness 24% 0.4–5%
Withdrawal 22% 4%
Lactational amenorrhea method
(6 months failure rate)
0–7.5% [25] <2% [26]

Birth control methods include barrier methods, hormonal birth control, intrauterine devices (IUDs), sterilization, and behavioral methods. They are used before or during sex while emergency contraceptives are effective for up to five days after sex. Effectiveness is generally expressed as the percentage of women who become pregnant using a given method during the first year, [27] and sometimes as a lifetime failure rate among methods with high effectiveness, such as tubal ligation. [28]

The most effective methods are those that are long acting and do not require ongoing health care visits. [29] Surgical sterilization, implantable hormones, and intrauterine devices all have first-year failure rates of less than 1%. [23] Hormonal contraceptive pills, patches or vaginal rings, and the lactational amenorrhea method (LAM), if adhered to strictly, can also have first-year (or for LAM, first-6-month) failure rates of less than 1%. [29] With typical use, first-year failure rates are considerably high, at 9%, due to inconsistent use. [23] Other methods such as condoms, diaphragms, and spermicides have higher first-year failure rates even with perfect usage. [29] The American Academy of Pediatrics recommends long acting reversible birth control as first line for young individuals. [30]

While all methods of birth control have some potential adverse effects, the risk is less than that of pregnancy. [29] After stopping or removing many methods of birth control, including oral contraceptives, IUDs, implants and injections, the rate of pregnancy during the subsequent year is the same as for those who used no birth control. [31]

For individuals with specific health problems, certain forms of birth control may require further investigations. [32] For women who are otherwise healthy, many methods of birth control should not require a medical exam—including birth control pills, injectable or implantable birth control, and condoms. [33] For example, a pelvic exam, breast exam, or blood test before starting birth control pills does not appear to affect outcomes. [34] [35] [36] In 2009, the World Health Organization (WHO) published a detailed list of medical eligibility criteria for each type of birth control. [32]

Hormonal Edit

Hormonal contraception is available in a number of different forms, including oral pills, implants under the skin, injections, patches, IUDs and a vaginal ring. They are currently available only for women, although hormonal contraceptives for men have been and are being clinically tested. [37] There are two types of oral birth control pills, the combined oral contraceptive pills (which contain both estrogen and a progestin) and the progestogen-only pills (sometimes called minipills). [38] If either is taken during pregnancy, they do not increase the risk of miscarriage nor cause birth defects. [35] Both types of birth control pills prevent fertilization mainly by inhibiting ovulation and thickening cervical mucus. [39] [40] They may also change the lining of the uterus and thus decrease implantation. [40] Their effectiveness depends on the user's adherence to taking the pills. [35]

Combined hormonal contraceptives are associated with a slightly increased risk of venous and arterial blood clots. [41] Venous clots, on average, increase from 2.8 to 9.8 per 10,000 women years [42] which is still less than that associated with pregnancy. [41] Due to this risk, they are not recommended in women over 35 years of age who continue to smoke. [43] Due to the increased risk, they are included in decision tools such as the DASH score and PERC rule used to predict the risk of blood clots. [44]

The effect on sexual desire is varied, with increase or decrease in some but with no effect in most. [45] Combined oral contraceptives reduce the risk of ovarian cancer and endometrial cancer and do not change the risk of breast cancer. [46] [47] They often reduce menstrual bleeding and painful menstruation cramps. [35] The lower doses of estrogen released from the vaginal ring may reduce the risk of breast tenderness, nausea, and headache associated with higher dose estrogen products. [46]

Progestin-only pills, injections and intrauterine devices are not associated with an increased risk of blood clots and may be used by women with a history of blood clots in their veins. [41] [48] In those with a history of arterial blood clots, non-hormonal birth control or a progestin-only method other than the injectable version should be used. [41] Progestin-only pills may improve menstrual symptoms and can be used by breastfeeding women as they do not affect milk production. Irregular bleeding may occur with progestin-only methods, with some users reporting no periods. [49] The progestins drospirenone and desogestrel minimize the androgenic side effects but increase the risks of blood clots and are thus not first line. [50] The perfect use first-year failure rate of injectable progestin is 0.2% the typical use first failure rate is 6%. [23]

Three varieties of birth control pills in calendar oriented packaging

Barrier Edit

Barrier contraceptives are devices that attempt to prevent pregnancy by physically preventing sperm from entering the uterus. [51] They include male condoms, female condoms, cervical caps, diaphragms, and contraceptive sponges with spermicide. [51]

Globally, condoms are the most common method of birth control. [52] Male condoms are put on a man's erect penis and physically block ejaculated sperm from entering the body of a sexual partner during intercourse and fellatio. [53] Modern condoms are most often made from latex, but some are made from other materials such as polyurethane, or lamb's intestine. [53] Female condoms are also available, most often made of nitrile, latex or polyurethane. [54] Male condoms have the advantage of being inexpensive, easy to use, and have few adverse effects. [55] Making condoms available to teenagers does not appear to affect the age of onset of sexual activity or its frequency. [56] In Japan, about 80% of couples who are using birth control use condoms, while in Germany this number is about 25%, [57] and in the United States it is 18%. [58]

Male condoms and the diaphragm with spermicide have typical use first-year failure rates of 18% and 12%, respectively. [23] With perfect use condoms are more effective with a 2% first-year failure rate versus a 6% first-year rate with the diaphragm. [23] Condoms have the additional benefit of helping to prevent the spread of some sexually transmitted infections such as HIV/AIDS, however, condoms made from animal intestine do not. [7] [59]

Contraceptive sponges combine a barrier with a spermicide. [29] Like diaphragms, they are inserted vaginally before intercourse and must be placed over the cervix to be effective. [29] Typical failure rates during the first year depend on whether or not a woman has previously given birth, being 24% in those who have and 12% in those who have not. [23] The sponge can be inserted up to 24 hours before intercourse and must be left in place for at least six hours afterward. [29] Allergic reactions [60] and more severe adverse effects such as toxic shock syndrome have been reported. [61]

A diaphragm vaginal-cervical barrier, in its case with a quarter U.S. coin.

A contraceptive sponge set inside its open package.

Intrauterine devices Edit

The current intrauterine devices (IUD) are small devices, often 'T'-shaped, containing either copper or levonorgestrel, which are inserted into the uterus. They are one form of long-acting reversible contraception which are the most effective types of reversible birth control. [62] Failure rates with the copper IUD is about 0.8% while the levonorgestrel IUD has a failure rates of 0.2% in the first year of use. [63] Among types of birth control, they, along with birth control implants, result in the greatest satisfaction among users. [64] As of 2007, IUDs are the most widely used form of reversible contraception, with more than 180 million users worldwide. [65]

Evidence supports effectiveness and safety in adolescents [64] and those who have and have not previously had children. [66] IUDs do not affect breastfeeding and can be inserted immediately after delivery. [67] They may also be used immediately after an abortion. [68] [69] Once removed, even after long term use, fertility returns to normal immediately. [70]

While copper IUDs may increase menstrual bleeding and result in more painful cramps, [71] hormonal IUDs may reduce menstrual bleeding or stop menstruation altogether. [67] Cramping can be treated with painkillers like non-steroidal anti-inflammatory drugs. [72] Other potential complications include expulsion (2–5%) and rarely perforation of the uterus (less than 0.7%). [67] [72] A previous model of the intrauterine device (the Dalkon shield) was associated with an increased risk of pelvic inflammatory disease, however the risk is not affected with current models in those without sexually transmitted infections around the time of insertion. [73] IUDs appear to decrease the risk of ovarian cancer. [74]

Sterilization Edit

Surgical sterilization is available in the form of tubal ligation for women and vasectomy for men. [2] There are no significant long term side effects, and tubal ligation decreases the risk of ovarian cancer. [2] Short term complications are twenty times less likely from a vasectomy than a tubal ligation. [2] [75] After a vasectomy, there may be swelling and pain of the scrotum which usually resolves in one or two weeks. [76] With tubal ligation, complications occur in 1 to 2 percent of procedures with serious complications usually due to the anesthesia. [77] Neither method offers protection from sexually transmitted infections. [2]

This decision may cause regret in some men and women. Of women aged over 30 who have undergone tubal ligation, about 5% regret their decision, as compared with 20% of women aged under 30. [2] By contrast, less than 5% of men are likely to regret sterilization. Men who are more likely to regret sterilization are younger, have young or no children, or have an unstable marriage. [78] In a survey of biological parents, 9% stated they would not have had children if they were able to do it over again. [79]

Although sterilization is considered a permanent procedure, [80] it is possible to attempt a tubal reversal to reconnect the fallopian tubes or a vasectomy reversal to reconnect the vasa deferentia. In women, the desire for a reversal is often associated with a change in spouse. [80] Pregnancy success rates after tubal reversal are between 31 and 88 percent, with complications including an increased risk of ectopic pregnancy. [80] The number of males who request reversal is between 2 and 6 percent. [81] Rates of success in fathering another child after reversal are between 38 and 84 percent with success being lower the longer the time period between the vasectomy and the reversal. [81] Sperm extraction followed by in vitro fertilization may also be an option in men. [82]

Behavioral Edit

Behavioral methods involve regulating the timing or method of intercourse to prevent introduction of sperm into the female reproductive tract, either altogether or when an egg may be present. [83] If used perfectly the first-year failure rate may be around 3.4%, however if used poorly first-year failure rates may approach 85%. [84]

Fertility awareness Edit

Fertility awareness methods involve determining the most fertile days of the menstrual cycle and avoiding unprotected intercourse. [83] Techniques for determining fertility include monitoring basal body temperature, cervical secretions, or the day of the cycle. [83] They have typical first-year failure rates of 24% perfect use first-year failure rates depend on which method is used and range from 0.4% to 5%. [23] The evidence on which these estimates are based, however, is poor as the majority of people in trials stop their use early. [83] Globally, they are used by about 3.6% of couples. [85] If based on both basal body temperature and another primary sign, the method is referred to as symptothermal. First-year failure rates of 20% overall and 0.4% for perfect use have been reported in clinical studies of the symptothermal method. [86] [23] A number of fertility tracking apps are available, as of 2016, but they are more commonly designed to assist those trying to get pregnant rather than prevent pregnancy. [87]

Withdrawal Edit

The withdrawal method (also known as coitus interruptus) is the practice of ending intercourse ("pulling out") before ejaculation. [88] The main risk of the withdrawal method is that the man may not perform the maneuver correctly or in a timely manner. [88] First-year failure rates vary from 4% with perfect usage to 22% with typical usage. [23] It is not considered birth control by some medical professionals. [29]

There is little data regarding the sperm content of pre-ejaculatory fluid. [89] While some tentative research did not find sperm, [89] one trial found sperm present in 10 out of 27 volunteers. [90] The withdrawal method is used as birth control by about 3% of couples. [85]

Abstinence Edit

Sexual abstinence may be used as a form of birth control, meaning either not engaging in any type of sexual activity, or specifically not engaging in vaginal intercourse, while engaging in other forms of non-vaginal sex. [91] [92] Complete sexual abstinence is 100% effective in preventing pregnancy. [93] [94] However, among those who take a pledge to abstain from premarital sex, as many as 88% who engage in sex, do so prior to marriage. [95] The choice to abstain from sex cannot protect against pregnancy as a result of rape, and public health efforts emphasizing abstinence to reduce unwanted pregnancy may have limited effectiveness, especially in developing countries and among disadvantaged groups. [96] [97]

Deliberate non-penetrative sex without vaginal sex or deliberate oral sex without vaginal sex are also sometimes considered birth control. [91] While this generally avoids pregnancy, pregnancy can still occur with intercrural sex and other forms of penis-near-vagina sex (genital rubbing, and the penis exiting from anal intercourse) where sperm can be deposited near the entrance to the vagina and can travel along the vagina's lubricating fluids. [98] [99]

Abstinence-only sex education does not reduce teenage pregnancy. [9] [100] Teen pregnancy rates and STI rates are generally the same or higher in states where students are given abstinence-only education, as compared with comprehensive sex education. [100] Some authorities recommend that those using abstinence as a primary method have backup methods available (such as condoms or emergency contraceptive pills). [101]

Lactation Edit

The lactational amenorrhea method involves the use of a woman's natural postpartum infertility which occurs after delivery and may be extended by breastfeeding. [102] This usually requires the presence of no periods, exclusively breastfeeding the infant, and a child younger than six months. [26] The World Health Organization states that if breastfeeding is the infant's only source of nutrition, the failure rate is 2% in the six months following delivery. [103] Six uncontrolled studies of lactational amenorrhea method users found failure rates at 6 months postpartum between 0% and 7.5%. [104] [ needs update ] Failure rates increase to 4–7% at one year and 13% at two years. [105] Feeding formula, pumping instead of nursing, the use of a pacifier, and feeding solids all increase its failure rate. [106] In those who are exclusively breastfeeding, about 10% begin having periods before three months and 20% before six months. [105] In those who are not breastfeeding, fertility may return four weeks after delivery. [105]

Emergency Edit

Emergency contraceptive methods are medications (sometimes misleadingly referred to as "morning-after pills") [107] or devices used after unprotected sexual intercourse with the hope of preventing pregnancy. Emergency contraceptives are often given to victims of rape. [10] They work primarily by preventing ovulation or fertilization. [2] [108] They are unlikely to affect implantation, but this has not been completely excluded. [108] A number of options exist, including high dose birth control pills, levonorgestrel, mifepristone, ulipristal and IUDs. [109] Providing emergency contraceptive pills to women in advance does not affect rates of sexually transmitted infections, condom use, pregnancy rates, or sexual risk-taking behavior. [110] [111] All methods have minimal side effects. [109]

Levonorgestrel pills, when used within 3 days, decrease the chance of pregnancy after a single episode of unprotected sex or condom failure by 70% (resulting in a pregnancy rate of 2.2%). [10] Ulipristal, when used within 5 days, decreases the chance of pregnancy by about 85% (pregnancy rate 1.4%) and is more effective than levonorgestrel. [10] [109] [112] Mifepristone is also more effective than levonorgestrel, while copper IUDs are the most effective method. [109] IUDs can be inserted up to five days after intercourse and prevent about 99% of pregnancies after an episode of unprotected sex (pregnancy rate of 0.1 to 0.2%). [2] [113] This makes them the most effective form of emergency contraceptive. [114] In those who are overweight or obese, levonorgestrel is less effective and an IUD or ulipristal is recommended. [115]

Dual protection Edit

Dual protection is the use of methods that prevent both sexually transmitted infections and pregnancy. [116] This can be with condoms either alone or along with another birth control method or by the avoidance of penetrative sex. [117] [118]

If pregnancy is a high concern, using two methods at the same time is reasonable. [117] For example, two forms of birth control are recommended in those taking the anti-acne drug isotretinoin or anti-epileptic drugs like carbamazepine, due to the high risk of birth defects if taken during pregnancy. [119] [120]

Health Edit

Contraceptive use in developing countries is estimated to have decreased the number of maternal deaths by 40% (about 270,000 deaths prevented in 2008) and could prevent 70% of deaths if the full demand for birth control were met. [19] [20] These benefits are achieved by reducing the number of unplanned pregnancies that subsequently result in unsafe abortions and by preventing pregnancies in those at high risk. [19]

Birth control also improves child survival in the developing world by lengthening the time between pregnancies. [19] In this population, outcomes are worse when a mother gets pregnant within eighteen months of a previous delivery. [19] [122] Delaying another pregnancy after a miscarriage however does not appear to alter risk and women are advised to attempt pregnancy in this situation whenever they are ready. [122]

Teenage pregnancies, especially among younger teens, are at greater risk of adverse outcomes including early birth, low birth weight, and death of the infant. [14] In the United States 82% of pregnancies in those between 15 and 19 are unplanned. [72] Comprehensive sex education and access to birth control are effective in decreasing pregnancy rates in this age group. [123]

Finances Edit

In the developing world, birth control increases economic growth due to there being fewer dependent children and thus more women participating in or increased contribution to the workforce. [21] Women's earnings, assets, body mass index, and their children's schooling and body mass index all improve with greater access to birth control. [21] Family planning, via the use of modern birth control, is one of the most cost-effective health interventions. [124] For every dollar spent, the United Nations estimates that two to six dollars are saved. [18] These cost savings are related to preventing unplanned pregnancies and decreasing the spread of sexually transmitted illnesses. [124] While all methods are beneficial financially, the use of copper IUDs resulted in the greatest savings. [124]

The total medical cost for a pregnancy, delivery and care of a newborn in the United States is on average $21,000 for a vaginal delivery and $31,000 for a caesarean delivery as of 2012. [125] In most other countries, the cost is less than half. [125] For a child born in 2011, an average US family will spend $235,000 over 17 years to raise them. [126]

Globally, as of 2009, approximately 60% of those who are married and able to have children use birth control. [128] How frequently different methods are used varies widely between countries. [128] The most common method in the developed world is condoms and oral contraceptives, while in Africa it is oral contraceptives and in Latin America and Asia it is sterilization. [128] In the developing world overall, 35% of birth control is via female sterilization, 30% is via IUDs, 12% is via oral contraceptives, 11% is via condoms, and 4% is via male sterilization. [128]

While less used in the developed countries than the developing world, the number of women using IUDs as of 2007 was more than 180 million. [65] Avoiding sex when fertile is used by about 3.6% of women of childbearing age, with usage as high as 20% in areas of South America. [129] As of 2005, 12% of couples are using a male form of birth control (either condoms or a vasectomy) with higher rates in the developed world. [130] Usage of male forms of birth control has decreased between 1985 and 2009. [128] Contraceptive use among women in Sub-Saharan Africa has risen from about 5% in 1991 to about 30% in 2006. [131]

As of 2012, 57% of women of childbearing age want to avoid pregnancy (867 of 1,520 million). [132] About 222 million women however were not able to access birth control, 53 million of whom were in sub-Saharan Africa and 97 million of whom were in Asia. [132] This results in 54 million unplanned pregnancies and nearly 80,000 maternal deaths a year. [128] Part of the reason that many women are without birth control is that many countries limit access due to religious or political reasons, [2] while another contributor is poverty. [133] Due to restrictive abortion laws in Sub-Saharan Africa, many women turn to unlicensed abortion providers for unintended pregnancy, resulting in about 2–4% obtaining unsafe abortions each year. [133]

Early history Edit

The Egyptian Ebers Papyrus from 1550 BC and the Kahun Papyrus from 1850 BC have within them some of the earliest documented descriptions of birth control: the use of honey, acacia leaves and lint to be placed in the vagina to block sperm. [134] [135] Silphium, a species of giant fennel native to north Africa, may have been used as birth control in ancient Greece and the ancient Near East. [136] [137] Due to its supposed desirability, by the first century AD, it had become so rare that it was worth more than its weight in silver and, by late antiquity, it was fully extinct. [136] Most methods of birth control used in antiquity were probably ineffective. [138]

The ancient Greek philosopher Aristotle (c. 384–322 BC) recommended applying cedar oil to the womb before intercourse, a method which was probably only effective on occasion. [138] A Hippocratic text On the Nature of Women recommended that a woman drink a copper salt dissolved in water, which it claimed would prevent pregnancy for a year. [138] This method was not only ineffective, but also dangerous, as the later medical writer Soranus of Ephesus (c. 98–138 AD) pointed out. [138] Soranus attempted to list reliable methods of birth control based on rational principles. [138] He rejected the use of superstition and amulets and instead prescribed mechanical methods such as vaginal plugs and pessaries using wool as a base covered in oils or other gummy substances. [138] Many of Soranus's methods were probably also ineffective. [138]

In medieval Europe, any effort to halt pregnancy was deemed immoral by the Catholic Church, [134] although it is believed that women of the time still used a number of birth control measures, such as coitus interruptus and inserting lily root and rue into the vagina. [139] Women in the Middle Ages were also encouraged to tie weasel testicles around their thighs during sex to prevent pregnancy. [140] The oldest condoms discovered to date were recovered in the ruins of Dudley Castle in England, and are dated back to 1640. [140] They were made of animal gut, and were most likely used to prevent the spread of sexually transmitted diseases during the English Civil War. [140] Casanova, living in 18th century Italy, described the use of a lambskin covering to prevent pregnancy however, condoms only became widely available in the 20th century. [134]

Birth control movement Edit

The birth control movement developed during the 19th and early 20th centuries. [141] The Malthusian League, based on the ideas of Thomas Malthus, was established in 1877 in the United Kingdom to educate the public about the importance of family planning and to advocate for getting rid of penalties for promoting birth control. [142] It was founded during the "Knowlton trial" of Annie Besant and Charles Bradlaugh, who were prosecuted for publishing on various methods of birth control. [143]

In the United States, Margaret Sanger and Otto Bobsein popularized the phrase "birth control" in 1914. [144] [145] Sanger primarily advocated for birth control on the idea that it would prevent women from seeking unsafe abortions, but during her lifetime, she began to campaign for it on the grounds that it would reduce mental and physical defects. [146] [147] She was mainly active in the United States but had gained an international reputation by the 1930s. At the time, under the Comstock Law, distribution of birth control information was illegal. She jumped bail in 1914 after her arrest for distributing birth control information and left the United States for the United Kingdom. [148] In the U.K., Sanger, influenced by Havelock Ellis, further developed her arguments for birth control. She believed women needed to enjoy sex without fearing a pregnancy. During her time abroad, Sanger also saw a more flexible diaphragm in a Dutch clinic, which she thought was a better form of contraceptive. [147] Once Sanger returned to the United States, she established a short-lived birth-control clinic with the help of her sister, Ethel Bryne, based in the Brownville section of Brooklyn, New York [149] in 1916. It was shut down after eleven days and resulted in her arrest. [150] The publicity surrounding the arrest, trial, and appeal sparked birth control activism across the United States. [151] Besides her sister, Sanger was helped in the movement by her first husband, William Sanger, who distributed copies of “Family Limitation.” Sanger's second husband, James Noah H. Slee, would also later become involved in the movement, acting as its main funder. [147]

The increased use of birth control was seen by some as a form of social decay. [152] A decrease of fertility was seen as a negative. Throughout the Progressive Era (1890-1920), there was an increase of voluntary associations aiding the contraceptive movement. [152] These organizations failed to enlist more than 100,000 women because the use of birth control was often compared to eugenics [152] however, there were women seeking a community with like-minded women. The ideology that surrounded birth control started to gain traction during the Progressive Era due to voluntary associations establishing community. Birth control was unlike the Victorian Era because women wanted to manage their sexuality. The use of birth control was another form of self-interest women clung to. This was seen as women began to gravitate towards strong figures, like the Gibson girl. [153]

The first permanent birth-control clinic was established in Britain in 1921 by Marie Stopes working with the Malthusian League. [154] The clinic, run by midwives and supported by visiting doctors, [155] offered women's birth-control advice and taught them the use of a cervical cap. Her clinic made contraception acceptable during the 1920s by presenting it in scientific terms. In 1921, Sanger founded the American Birth Control League, which later became the Planned Parenthood Federation of America. [156] In 1924 the Society for the Provision of Birth Control Clinics was founded to campaign for municipal clinics this led to the opening of a second clinic in Greengate, Salford in 1926. [157] Throughout the 1920s, Stopes and other feminist pioneers, including Dora Russell and Stella Browne, played a major role in breaking down taboos about sex. In April 1930 the Birth Control Conference assembled 700 delegates and was successful in bringing birth control and abortion into the political sphere – three months later, the Ministry of Health, in the United Kingdom, allowed local authorities to give birth-control advice in welfare centres. [158]

The National Birth Control Association was founded in Britain in 1931, and became the Family Planning Association eight years later. The Association amalgamated several British birth control-focused groups into 'a central organisation' for administering and overseeing birth control in Britain. The group incorporated the Birth Control Investigation Committee, a collective of physicians and scientists that was founded to investigate scientific and medical aspects of contraception with 'neutrality and impartiality'. [159] Subsequently, the Association effected a series of 'pure' and 'applied' product and safety standards that manufacturers must meet to ensure their contraceptives could be prescribed as part of the Association's standard two-part-technique combining ‘a rubber appliance to protect the mouth of the womb’ with a ‘chemical preparation capable of destroying. sperm’. [160] Between 1931 and 1959, the Association founded and funded a series of tests to assess chemical efficacy and safety and rubber quality. [161] These tests became the basis for the Association's Approved List of contraceptives, which was launched in 1937, and went on to become an annual publication that the expanding network of FPA clinics relied upon as a means to 'establish facts [about contraceptives] and to publish these facts as a basis on which a sound public and scientific opinion can be built'. [162]

In 1936, the United States Court of Appeals for the Second Circuit ruled in United States v. One Package of Japanese Pessaries that medically prescribing contraception to save a person's life or well-being was not illegal under the Comstock Laws. Following this decision, the American Medical Association Committee on Contraception revoked its 1936 statement condemning birth control. [ citation needed ] A national survey in 1937 showed 71 percent of the adult population supported the use of contraception. [ citation needed ] By 1938, 347 birth control clinics were running in the United States despite their advertisement still being illegal. [ citation needed ] First Lady Eleanor Roosevelt publicly supported birth control and family planning. [163] The restrictions on birth control in the Comstock laws were effectively rendered null and void by Supreme Court decisions Griswold v. Connecticut (1965) [164] and Eisenstadt v. Baird (1972). [165] In 1966, President Lyndon B. Johnson started endorsing public funding for family planning services, and the Federal Government began subsidizing birth control services for low-income families. [166] The Affordable Care Act, passed into law on March 23, 2010 under President Barack Obama, requires all plans in the Health Insurance Marketplace to cover contraceptive methods. These include barrier methods, hormonal methods, implanted devices, emergency contraceptives, and sterilization procedures. [167]

Modern methods Edit

In 1909, Richard Richter developed the first intrauterine device made from silkworm gut, which was further developed and marketed in Germany by Ernst Gräfenberg in the late 1920s. [168] In 1951, an Austrian-born American chemist, named Carl Djerassi at Syntex in Mexico City made the hormones in progesterone pills using Mexican yams (Dioscorea mexicana). [169] Djerassi had chemically created the pill but was not equipped to distribute it to patients. Meanwhile, Gregory Pincus and John Rock with help from the Planned Parenthood Federation of America developed the first birth control pills in the 1950s, such as mestranol/noretynodrel, which became publicly available in the 1960s through the Food and Drug Administration under the name Enovid. [156] [170] Medical abortion became an alternative to surgical abortion with the availability of prostaglandin analogs in the 1970s and mifepristone in the 1980s. [171]

Legal positions Edit

Human rights agreements require most governments to provide family planning and contraceptive information and services. These include the requirement to create a national plan for family planning services, remove laws that limit access to family planning, ensure that a wide variety of safe and effective birth control methods are available including emergency contraceptives, make sure there are appropriately trained healthcare providers and facilities at an affordable price, and create a process to review the programs implemented. If governments fail to do the above it may put them in breach of binding international treaty obligations. [172]

In the United States, the 1965 Supreme Court decision Griswold v. Connecticut overturned a state law prohibiting dissemination of contraception information based on a constitutional right to privacy for marital relationships. In 1971, Eisenstadt v. Baird extended this right to privacy to single people. [173]

In 2010, the United Nations launched the Every Woman Every Child movement to assess the progress toward meeting women's contraceptive needs. The initiative has set a goal of increasing the number of users of modern birth control by 120 million women in the world's 69 poorest countries by the year 2020. Additionally, they aim to eradicate discrimination against girls and young women who seek contraceptives. [174] The American Congress of Obstetricians and Gynecologists (ACOG) recommended in 2014 that oral birth control pills should be over the counter medications. [175]

Since at least the 1870s, American religious, medical, legislative, and legal commentators have debated contraception laws. Ana Garner and Angela Michel have found that in these discussions men often attach reproductive rights to moral and political matters, as part of an ongoing attempt to regulate human bodies. In press coverage between 1873–2013 they found a divide between institutional ideology and real-life experiences of women. [176]

Religious views Edit

Religions vary widely in their views of the ethics of birth control. [177] The Roman Catholic Church re-affirmed its rejection of artificial contraception in 1968 and only accepts natural family planning, [178] although large numbers of Catholics in developed countries accept and use modern methods of birth control. [179] [180] [181] Among Protestants, there is a wide range of views from supporting none, such as in the Quiverfull movement, to allowing all methods of birth control. [182] Views in Judaism range from the stricter Orthodox sect, which prohibits all methods of birth control, to the more relaxed Reform sect, which allows most. [183] Hindus may use both natural and modern contraceptives. [184] A common Buddhist view is that preventing conception is acceptable, while intervening after conception has occurred is not. [185] In Islam, contraceptives are allowed if they do not threaten health, although their use is discouraged by some. [186]

World Contraception Day Edit

September 26 is World Contraception Day, devoted to raising awareness and improving education about sexual and reproductive health, with a vision of a world where every pregnancy is wanted. [187] It is supported by a group of governments and international NGOs, including the Office of Population Affairs, the Asian Pacific Council on Contraception, Centro Latinamericano Salud y Mujer, the European Society of Contraception and Reproductive Health, the German Foundation for World Population, the International Federation of Pediatric and Adolescent Gynecology, International Planned Parenthood Federation, the Marie Stopes International, Population Services International, the Population Council, the United States Agency for International Development (USAID), and Women Deliver. [187]

Misconceptions Edit

There are a number of common misconceptions regarding sex and pregnancy. [188] Douching after sexual intercourse is not an effective form of birth control. [189] Additionally, it is associated with a number of health problems and thus is not recommended. [190] Women can become pregnant the first time they have sexual intercourse [191] and in any sexual position. [192] It is possible, although not very likely, to become pregnant during menstruation. [193] Contraceptive use regardless of its duration and type does not have a negative effect on the ability of women to conceive following termination of use and it doesn’t significantly delay fertility. On the other hand, women who used oral contraceptives for a longer duration may had a slightly lower rate of pregnancy than did women using oral contraceptives for a shorter period of time which could be the effect of age, in which fertility decreases as age advances. [194]

Accessibility Edit

Access to birth control may be affected by finances and the laws within a region or country. [195] In the United States African American, Hispanic, and young women are disproportionately affected by limited access to birth control, as a result of financial disparity. [196] [197] For example Hispanic and African American women often lack insurance coverage and are more often poor. [198] New immigrants in the United States are not offered preventive care such as birth control. [199]

Females Edit

Improvements of existing birth control methods are needed, as around half of those who get pregnant unintentionally are using birth control at the time. [29] A number of alterations of existing contraceptive methods are being studied, including a better female condom, an improved diaphragm, a patch containing only progestin, and a vaginal ring containing long-acting progesterone. [200] This vaginal ring appears to be effective for three or four months and is currently available in some areas of the world. [200] For women who rarely have sex, the taking of the hormonal birth control levonorgestrel around the time of sex looks promising. [201]

A number of methods to perform sterilization via the cervix are being studied. One involves putting quinacrine in the uterus which causes scarring and infertility. While the procedure is inexpensive and does not require surgical skills, there are concerns regarding long-term side effects. [202] Another substance, polidocanol, which functions in the same manner is being looked at. [200] A device called Essure, which expands when placed in the fallopian tubes and blocks them, was approved in the United States in 2002. [202] In 2016, a black boxed warning regarding potentially serious side effects was added, [203] [204] and in 2018, the device was discontinued. [205]

Males Edit

Methods of male birth control include condoms, vasectomies and withdrawal. [206] [207] Between 25 and 75% of males who are sexually active would use hormonal birth control if it was available for them. [130] [206] A number of hormonal and non-hormonal methods are in trials, [130] and there is some research looking at the possibility of contraceptive vaccines. [208]

A reversible surgical method under investigation is reversible inhibition of sperm under guidance (RISUG) which consists of injecting a polymer gel, styrene maleic anhydride in dimethyl sulfoxide, into the vas deferens. An injection with sodium bicarbonate washes out the substance and restores fertility. Another is an intravas device which involves putting a urethane plug into the vas deferens to block it. A combination of an androgen and a progestin seems promising, as do selective androgen receptor modulators. [130] Ultrasound and methods to heat the testicles have undergone preliminary studies. [209]

Neutering or spaying, which involves removing some of the reproductive organs, is often carried out as a method of birth control in household pets. Many animal shelters require these procedures as part of adoption agreements. [210] In large animals the surgery is known as castration. [211]

Birth control is also being considered as an alternative to hunting as a means of controlling overpopulation in wild animals. [212] Contraceptive vaccines have been found to be effective in a number of different animal populations. [213] [214] Kenyan goat herders fix a skirt, called an olor, to male goats to prevent them from impregnating female goats. [215]


Scientists Found Sperm’s Power Switch—And a Way to Turn It Off

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Condoms have come a long way from the linen and animal bladder sheaths used by the ancient Greeks, Romans, and Egyptians. But the tenets of modern male birth control are no different now than they were then: Keep sperm away from eggs. In the US, some 5.7 million women still rely on the male condom as their primary form of birth control.

But setting up a barrier isn’t the only way to keep sperm from fertilizing eggs. To succeed in their mission, sperm have to be good at two things: swimming and drilling. Most birth control, including condoms, targets the swimming portion of the baby-making biathlon scientists haven’t been able to pull the plug on the sperm drilling operation itself. But now, using measurements of ion currents inside a single sperm, they’ve found the power switch—and a way to turn it off. The result, they say, could be a more effective contraceptive, and one that would work equally as well in men as in women.

To make their way from the cervix, through the uterus, and into a fallopian tube, sperm cells beat their tails side to side like a snake cutting across the countryside. It’s good for covering long (relative) distances: Human sperm have to swim 10 to 12 centimeters, or 24,000 times their own body length, to reach the egg. But that tail waggle is totally useless for pushing through an egg’s thick protective layer, called the zona pellucida. That barrier stands between a sperm and its Darwinian destiny.

The head of a human sperm is just five puny microns long. To get through the 30-micron-deep zona pellucida, it has to turn its tail into a powerful drill. Instead of beating side to side, it starts to turn in only one direction, corkscrewing the head forward, through the dense, viscous environment of the egg’s outer layers. Scientists call this maneuver the “power kick.”

And what powers the power kick? A massive dump of calcium ions into the sperm’s tail. (Ion transfer across membranes is how cells generate the electricity they need to power motor function.)

While there are thousands of different kinds of ion channels in every cell in the human body, the power kick relies on just one, found only in sperm. Its name is Catsper. And it only activates to let calcium in when it gets close to an egg and encounters progesterone. Scientists have known about Catsper (the friendly, sperm-specific ion channel) since 2001, when they stumbled across it while studying male infertility. The patients, it turned out, had a mutation in at least one of the nine genes that code for Catsper.

In a paper published today in PNAS, researchers at UC Berkeley screened more than 50 chemical compounds to find a few that could tightly bind with Catsper, gumming up its channel and preventing the calcium dump needed for a power kick. The two most promising ones both come from plants that humans have been consuming for millennia: lupeol, a compound found in mangos, grapes, and olives, and pristimerin, which comes from an ancient medicinal herb known as the “Thunder God Vine.” (Presumably the thunder god didn’t also preside over matters of fertility.)

“This could be used immediately to make a better and more efficient emergency contraceptive,” says study leader and biophysicist Polina Lishko. She points out that one of the biggest controversies over current Plan B options is that they sometimes work by preventing a fertilized egg from attaching to the uterus. That debate leaves current emergency contraception options vulnerable to anti-abortion advocates who believe life starts at conception. “This method is not only 10 times more effective than anything currently on the market, but it clearly prevents fertilization,” Lishko says. “There’s no embryo at any point.”

But it’s the potential for an effective male contraceptive that has Erwin Goldberg excited. A molecular biologist and sperm researcher at Northwestern University, he says the study, from a scientific perspective, should make a compelling pitch to drug developers. “We haven’t had anything new in the realm of male contraceptives since the introduction of the condom,” he says. A number of high-profile injectable hormonal male contraceptives have failed over the years or been stopped short for concern over side effects.

One notable exception is Vasalgel, a gel-like barrier that is injected into the vas deferens to block sperm. In February it passed a primate trial, and is headed towards humans next. The Berkeley researchers are a few steps behind that, but Goldberg still thinks they’re on to something. “As far as developing a new male contraception I personally think this is an important idea,” he says. But, he points out, pharmaceutical companies still have to believe there’s a demand for that sort of thing in order to back expensive clinical trials.

The results Lishko and her team published today came from measurements they made on human sperm in the lab. But they recently began trials in primates to see how long the drill-disabling effect lasts in the body, and to work out proper doses. She expects those results later this year. They’ll be important for the plans she has to start a company and commercialize the compounds within the next three years. The goal is what Lishko calls a universal contraceptive: one that works for both men and women and could be taken either orally or released slowly through an implantable ring. That would bring some much-needed gender equity to the pregnancy prevention pantheon. No drill, no baby, no drill.


Non-hormonal approaches acting on the epididymis

The epididymis is responsible for concentrating sperm within the seminiferous fluid and conditioning the lipids and proteins on the surface of the sperm. This process takes several weeks and is essential for maturation of the sperm to improve their functionality. There are several areas currently being explored as potential sites of intervention for a male contraceptive. There are proteins, for example Eppin,29 expressed in the epididymis (and nowhere else in the body) that could be targeted with drugs that disrupt their functions. As these proteins are only expressed in the reproductive tract, there should theoretically be few side effects to these methods.29


Clinical development

Clinical trial considerations

Clinical trials for contraceptive products present a unique set of considerations given the population (young, healthy individuals) and outcome (pregnancy) of interest. Selecting the right inclusion criteria at all stages of clinical development to maximize the collection of necessary and appropriate data yet not limit/inhibit enrollment can be challenging. For example, for Phase 1 trials of female methods, requiring women to be at low risk of pregnancy yet not using hormonal contraceptives can lead to difficulties in recruitment. For early phase male contraceptive studies, defining potential risk to a female partner must also be considered (e.g., if a drug would be found in semen to which women would be exposed). Selecting the right trial sites is also important. For example, academic centers, while frequently having experienced investigators, might not be the best settings for Phase 1 trials due to slower enrollment. If rapid, efficient recruitment and extensive PK sampling and frequent visits are needed, dedicated Phase 1 facilities might be a better option. With regard to contraceptive steroid analysis, choosing the right laboratory and assays for PK analyses is important. For trials of male contraceptives, ensuring alignment and quality control of laboratories doing semen evaluations would be important.

In the first few small studies of methods with NCEs, adverse event (AE) and serious adverse event (SAE) numbers are likely to be very low and possibly unrepresentative of the safety profile of the investigational product. This can make signal detection difficult. Signal detection in pharmacovigilance involves looking at cumulative adverse reaction data for patterns that suggest new safety concerns. One potential way to improve on signal detection is to collaborate with other investigators using the same API and create platforms for sharing of safety data.

The role of pharmacokinetics

For many drugs in other areas, the therapeutic window, or the range of drug doses which are highly effective while still safe, can be readily characterized. This, however, is not as straightforward for contraceptive steroids. While initial clinical trials define the PK of a new formulation, the reliance on PK to determine appropriate doses for further efficacy evaluation can be complicated. Even for methods such as contraceptive implants which release fairly constant levels of drug over many years, the contraceptive threshold in terms of blood levels that maintain a high level of effectiveness remains elusive and may be influenced by multiple factors [ 6]. The presumed contraceptive threshold for levonorgestrel implants, which do not consistently suppress ovulation, was determined by retrospectively evaluating serum hormone levels above which pregnancies were consistently prevented. In contrast, for etonogestrel implants, the presumed contraceptive threshold was based on a level at which most women had suppression of ovulation (a surrogate marker of effectiveness in pregnancy prevention). While surrogate markers such as ovulation inhibition are more likely to indicate risk of pregnancy than PK alone, they are not necessarily completely predictive. For example, even if ovulation occurs, it may be abnormal, or other effects of hormonal contraceptives, such as thickening of cervical mucus and thinning of the uterine endometrium, may prevent conception and implantation even if ovulation occurs. These issues should also be considered for any new nonhormonal female or male contraceptive.

Pharmacokinetic parameters of contraceptive steroids also vary greatly within and between individuals. Part of this variability may be due to assay variations (i.e., in historical published literature) as well as true ethnic differences in the amount of hepatic metabolism. Factors such as diet, concurrent illness, smoking, or weight may also affect steroid PK, further complicating study population selection. These factors must be considered when selecting clinical sites and developing study eligibility criteria. The selection of study populations may limit labeling and should be considered in product development planning. While our experience is primarily with contraceptive steroids, PK variability is seen with many other drugs as well.

Drug–drug interactions

Early in development, developers should also consider how the effectiveness of a drug might be influenced by other drugs or other things that could influence metabolism of the drug (e.g., grapefruit juice). The FDA has recently put out guidance on the design of drug–drug interaction (DDI) studies to help investigators design and evaluate DDIs studies during development [ 7]. Individuals often use more than one drug at a time, and this could compromise the effectiveness or safety of either drug and lead to morbidity and mortality. Not knowing about other drug use can also compromise data and study conclusions (e.g., PK and/or safety assessments). DDIs are particularly relevant for hormonal contraceptive methods. In the liver, cytochrome P450 enzymes catalyze the most important metabolic reactions, with the most significant for progestin metabolism being cytochrome P450 3A, particularly polypeptide 4 (CYP3A4). Many progestins are substrates for CYP3A4, and different progestins themselves have varying effects on CYP enzymes. The effectiveness of any contraceptive may be compromised if PK parameters are affected by other drugs to such an extent that primary mechanisms of action are inhibited. Contraceptives may also affect the metabolism of other drugs, leading to issues with effectiveness or safety of the co-administered medication, and in vitro assays may not predict in vivo drug interactions. Further, these interactions may be complex, particularly when multiple, possibly interacting, drugs are involved and used long term. For progestin-only contraceptives, DDIs with liver enzyme-inducing medications such as antiretrovirals have led to decreases in effectiveness of even highly effective long-acting contraceptive methods, such as implants [ 8]. In addition, there may be polymorphisms of CYP3A4 genes in various populations, leading to differences in metabolism of contraceptive steroids [ 9] and other drugs metabolized by this enzyme.

Unique considerations for male methods

Finally, unique new challenges may occur with newer nonhormonal methods. In women, suppression of ovulation is achieved for currently available methods by suppression of gonadotropins. In men, suppression of sperm production may occur at various levels, all with their own unique challenges and potential adverse effects. New ethical issues may also arise. For example, newer methods in development may modify the germline. In such cases concerns are increased regarding the impact of unintended pregnancy, particularly on male fetuses.

Additional lessons learned from clinical trials for female contraceptives

FHI 360 has been leading contraceptive clinical trials for decades. Again, due in large part to the lack of pharmaceutical industry interest in developing new contraceptive products, particularly for use in LMICs, international organizations like FHI 360 have led clinical development programs of many technologies. Although most of our previous work has been in LMICs, much of the experience we have gained is also relevant to high-income countries (HICs).

One ubiquitous lesson we have learned in this long history is that consistently high effectiveness in preventing pregnancy requires longer-acting methods (generally preventing pregnancy for at least a month). With short-acting methods (e.g., pills, barriers), effectiveness differs between perfect use and typical use [ 10]. Perfect use effectiveness rates are calculated using consistent and correct use, while typical use effectiveness generally refers to effectiveness while a method is reportedly being used but may not be used consistently, continuously, or correctly. Inconsistent or incorrect use leads to unintended pregnancy in many users [ 11]. Long-acting methods that do not require user action, such as IUDs and implants, lead to higher effectiveness, with both very high typical and perfect use effectiveness rates [ 12]. Partly because of this potential for high effectiveness, as well as user preference, which we have discovered through acceptability research described in the next section, our recent development work has focused on longer-acting methods such as injectables, IUDs, and implants ( Box 3).

Lessons learned from female contraceptive development

• High effectiveness requires long-acting forgettable methods, such as implants or longer-acting injectables.

• Self-injection improves adherence to injectable contraceptives.

• Some delivery systems such as implants require training and support to ensure that insertion and removal challenges do not occur when used at scale.

• Biodegradable implants have the potential to mitigate removal challenges and reduce burdens on the healthcare system by eliminating the need for removal.

Injectable contraceptives remain very popular among users, particularly in low-resource settings. However, intramuscular injectables such as DMPA-IM (e.g., Depo-Provera), which are intermediate acting but require some user action (reinjection every 3 months) also have lower typical use effectiveness than perfect use effectiveness due to failure to get reinjections on time. Although method-related concerns, such as side effects, are the most commonly reported reasons for discontinuation of injectables, access to reinjection services also remains a problem in low-resource settings [ 13]. Our research has shown that even a 3-month interval between injections is ultimately too frequent for many women, spurring interest in the development of a longer-acting product. Less frequent clinic visits would also reduce burden on women and providers [ 13–15].

In many LMIC settings, access to healthcare providers is limited. Even in HICs, discontinuation of injectable contraceptives due to failure to return for reinjection (due to inconvenience or cost) may be an issue. Thus, other efforts to improve method continuation rates have evaluated self-care. The WHO defines self-care as “the ability of individuals, families and communities to promote and maintain health, prevent disease, and cope with illness and disability with or without the support of a healthcare provider” [ 16]. Part of our research efforts thus focus on new longer-acting contraceptive technologies that have the potential for self-administration. Our research has also shown that self-administration of currently available contraceptives can improve method continuation rates. In a randomized trial of an existing subcutaneous 3-month DMPA formulation (Sayana Press), we found that a significantly higher rate of 1-year continuation among women who self-injected compared with those assigned to return to a provider for the injections [ 17]. Self-administration also has the potential to improve method continuation in the United States and other HICs [ 18].

While long-acting methods such as IUDs and contraceptive implants have led to improved effectiveness comparable to permanent contraception, the insertion and removal of long-acting, provider-administered methods can be challenging. Insertion and removal issues are often not evident in the highly structured and controlled clinical trials used for method approval or even in initial introductory trials. When used at larger scale, however, especially in lower-resource settings, methods requiring insertion by a trained provider may have lower effectiveness due to variations in successful administration. Additionally, removal issues may also present problems [ 19, 20]. Thus, introduction of methods such as implants should be accompanied by extensive training on insertion and removal as well as method-related counseling. To mitigate issues with removal of contraceptive implants, we are investigating the use of biodegradable implants which, though requiring a provider for insertion, will not require removal, thus reducing this burden on the healthcare system.


Conclusions

Our experience leads us to the following conclusions. First, several product development programs exist today that demonstrate exciting possibilities for the future of contraceptive development, such as on-demand male contraception and MPTs. Second, product development pipelines should be balanced in terms of risk vs innovation, marketing strategy, and customer expectations. Third, the development of novel delivery devices and innovative biological technologies will continue to help drive contraceptive development. Fourth, non-targeted contraceptive development programs offer advantages of shorter product optimization timelines, which equate to reduced preclinical development costs and time to market. The environments for product development in industry and academia are inherently different, and important lessons can be learned from understanding the strengths of each setting and the opportunities for meaningful collaboration.


Why Is There No Male Birth Control Yet?

The injustice of our current contraceptive regime needs no elaboration. Enough to say that it’s bizarre, at this late date, that male birth control still does not exist. Every couple of years some scientist says they’re on the brink, and the same stale monologue jokes are hauled out of storage afterwards they are placed back on the shelf, with no expectation, on anyone’s part, that they’ve been heard for the last time.

What’s the obstacle here, exactly? Is it a lack of effort, or funding, or what? What specifically is it about society, or science, or the inner properties of the dick/ball system, that has to this point prevented the invention of male birth control? For this week’s Giz Asks , we reached out to a number of experts to find out.

Lisa Campo-Engelstein

Associate Professor and Associate Director at the Alden March Bioethics Institute and Associate Professor of Obstetrics & Gynecology at Albany Medical College

Some argue that it’s the science—that it’s much harder to control millions of sperm, versus one egg. But I don’t think that’s the entire picture. I think there are many other factors involved, and that a lot of them have to do with gender norms.

For instance: we tend to conflate reproduction with women, and so assume that all reproductive matters are “women’s issues.” When we have that mentality, we ignore male reproduction—we overlook it altogether. Most people have never even heard of the field of andrology, which is the study of the male reproductive system. It’s not taught much in medical schools—and if students aren’t learning this stuff, how are they going to provide these services? It’s not surprising, then, that we didn’t start working on hormonal methods of contraception for men until 50 years after we started working on them for women.

Another major issue is that drug development requires the deep pockets of pharmaceutical companies—researchers can’t move forward exclusively with funding from NIH or other non-profit organizations. And pharmaceutical companies have not been interested. They say it’s not going to make money—that men are uninterested and that women won’t trust men to take it. But we actually have good empirical data contradicting both of those claims.

The Male Contraceptive Initiative, for instance, a non-profit looking to create more male contraception, just did a survey earlier this year reaching out to men of reproductive age to ask if they would be interested, and a large majority really were. And as for women not trusting men—pharmaceutical companies don’t seem to distinguish between casual sex partners and committed partners. Of course women aren’t going to trust casual sex partners—we don’t trust male strangers in all sorts of contexts. But there was one study that showed that 98% of women would trust their committed partner. Women trust their male partner on all sorts of high stakes things—if you’re in a partnership, that’s what you do. I’m hopeful these are maybe signs of change—but then, they’ve been saying the male pill is around the corner for 50 years.

Arthi Thirumalai

Assistant Professor, Metabolism, Endocrinology and Nutrition at UW School of Medicine

One historical challenge to the development of male birth control has been the notion that men would not be interested in taking it, or could not be relied upon to take it. But surveys and studies are showing us that that’s not the case any longer—that men are definitely interested in sharing the responsibilities of family planning, and are enthusiastic about the prospect of male birth control.

Another challenge has been a lack of pharmaceutical industry funding. Research at this time is mostly driven by big research centers and government funding.

It’s also important to distinguish between hormonal and non-hormonal methods. Hormonal methods essentially alter how testosterone is produced in the male body, and how sperm is produced in the body. With those methods, the main hiccup is that altering hormonal levels causes side effects—changes in mood, acne, sexual dysfunction. It becomes a tolerability question: how much will men put up with? What dose is it safe to ingest at a given time? The bigger bar for the hormonal method, though, is being able to bring the sperm count low enough, so that the drug becomes a reliable method of birth control. So that’s the challenge: the dose can’t be so high as to cause bad side effects, but it needs to be low enough to reliably suppress the sperm count.

One of the main problems with the hormonal method is that most of them have used injections, and injections come with their own issues—they have to be combined with different agents called progestins, and so we can’t really ever be sure what’s causing certain side effects.

On the non-hormonal end, what they’re aiming to do it use methods that prevent the sperm from either being active or from being released in some way, and none of those methods have come as far as the hormonal method in terms of reversibility—most are currently sort of sterilization methods, and their failure rates are high.

Eli Ipp

Professor of Medicine at UCLA, Investigator at the Lundquist institute, and Head of the Section of Diabetes and Metabolism, Harbor-UCLA Medical Center

People interested in family planning have been thinking about male contraception for a long time. We’re presently working on some of these issues, under the auspices of the National Institutes of Health and the National Institute of Child Health and Human Development, two federal agencies that are supporting research into contraception through what’s called a contraceptive clinical trials network. Dr. Christina Wang, is the principle investigator of the project.

The idea is that family planning should be a shared experience—that men and women could contribute according to their wishes. We want to expand the options that are available for family planning. There have been a number of studies that have looked at acceptability of male directed contraceptives, and many are surprised to find that there’s a positive response from men and from women.

Right now, we are working with a number of different hormonal agents. These agents may be administered transdermally—applied to the skin—or they can be applied by injection, or they can be given as an oral agent. All of them operate on the concept of combining an androgen—a male hormone, like testosterone—and a progestogen, which is also used in female contraception treatments, such as oral birth control pills. This combination is much more effective than suppressing the male’s sperm count.

We’ve used combinations before in various types of trials, and they’ve proven to be effective. The largest study we’re doing right now is taking place worldwide, with sites in South America, Europe, Africa, and the United States. We’re hoping that the effect will be a positive one in terms of protection of fertility, and that it will be acceptable to the individuals, and of course reversible when recipients of the medication are ready to move ahead with having a family.

Katrina Kimport

Associate Professor, Obstetrics, Gynecology & Reproductives Sciences, Advancing New Standards in Reproductive Health, University of California, San Francisco

There already is male birth control. At least, there are methods of contraception that operate in or are controlled primarily by male bodies: condoms, withdrawal, and vasectomy. The trick is that many people—both men and women—are unsatisfied with these methods. If you might want children later, vasectomy isn’t going to work. If you want a method with a very high rate of preventing pregnancy (like over 95%), condoms or withdrawal are probably not for you. If you want a reversible, highly effective method, methods that work in female bodies are all that’s available.

Why, then, isn’t there reversible, highly effective male birth control yet? A big part of the answer is that, as a society, we consider the work of pregnancy prevention to be women’s work. The pharmaceutical and medical infrastructure expects women to be the ones in a heterosexual relationship who are contracepting—and going to the doctor to get a method, paying for the method, and experiencing any side effects—so available methods are made for female bodies and only women receive contraceptive counseling from their healthcare providers. And the socially-normalized relationship trajectory reinforces this idea, too: as a sign that a relationship is serious, women shoulder the burden of preventing pregnancy by, say, going on the pill. At multiple levels, powerful social narratives feminize responsibility for birth control. In so doing, they simultaneously assert that there is no need or demand for reversible, highly effective male birth control.


Contraceptive Effectiveness external icon

Source: Trussell J, Aiken ARA, Micks E, Guthrie KA. Efficacy, safety, and personal considerations. In: Hatcher RA, Nelson AL, Trussell J, Cwiak C, Cason P, Policar MS, Edelman A, Aiken ARA, Marrazzo J, Kowal D, eds. Contraceptive technology. 21st ed. New York, NY: Ayer Company Publishers, Inc., 2018.