The Coming Birth-Control Revolution

Within the next couple of decades, a new generation of contraceptives could hit the American market. One, a pill that blocks certain cells from accessing vitamin A, might be able to limit fertility without flooding the body with hormones; another is an injection that temporarily blocks up the reproductive plumbing. The method that’s furthest along in trials is a topical gel that promises to induce temporary infertility when smeared daily on the shoulders and upper arms—without affecting mood or libido. “Overall, we don’t have any serious adverse events at all,” Christina Wang, a contraceptive researcher at the Lundquist Institute in California, and one of the developers of the gel, told me.

This coming slew of treatments will be notable not only for their imaginative delivery methods, but for their target audience: men. For decades, men hoping to manage their fertility have been limited to just two imperfect options—condoms or vasectomies. But in recent years, researchers have taken massive steps toward developing simple, convenient, and effective contraceptive options for men with virtually zero side effects. Soon, women may not be forced to bear nearly the entire burden of preventing pregnancy.

But the coming innovations won’t just be about expanding the menu of options for men. Better male contraception wouldn’t be on the way if not for the many scientific paths that female contraception has paved. Now women’s birth control—much of which still comes with plenty of irksome, sometimes risky, side effects—seems due for some kickbacks. True, the logistics of keeping an egg from exiting an ovary don’t completely overlap with the mechanics of keeping sperm out of the female reproductive tract. But in principle, “there are a lot of similarities,” Diana Blithe, the chief of the NIH’s Contraceptive Development Program, told me, which means one can easily inform the other. With an eye on what’s now being accomplished for male contraception, researchers may soon be able to deliver to women new forms of birth control that aren’t just more tolerable, but also more on-demand, less invasive, or even usable on male and female reproductive systems alike.

In the six-plus decades since the debut of the birth-control pill, the list of contraceptive choices for women has lengthened impressively. People can opt for barrier methods, or choose among pills, patches, and implants; they can receive injections a few times a year, or select an intrauterine device that can last up to 10 years. “We have so many options, it’s almost like you’re in a cereal aisle,” Amy Alspaugh, a nurse and reproductive-health researcher at the University of Tennessee at Knoxville, told me.

Read: The calendar of human fertility is changing

Many methods are also ever-improving: IUDs, implants, and injections now have longer lifespans and are easier to insert and remove; doses of hormonal contraception have dramatically decreased. “We used to give basically like a horse dose of estrogen and progestin,” Alspaugh told me. “Now we give the lowest dose that we know we can give and still have it be effective,” in order to minimize side effects. Some researchers have been exploring new ways to deliver contraception—microneedles, for instance, or even microchip technology that might allow women to remotely tune their birth control. (The latter idea has raised privacy concerns galore.) The Population Council, an NGO based in New York, has been working on a multipurpose vaginal ring that will, in addition to preventing pregnancy, release an antiviral to protect women against HIV, Régine Sitruk-Ware, a reproductive endocrinologist and contraception researcher at the nonprofit, told me.

By and large, though, the changes to female contraception have been incremental—more ingredient swaps than whole new recipes. Categorically, “we’ve had the same offerings for pretty much 30 years now,” Heather Vahdat, the executive director of the Male Contraceptive Initiative, told me. And plenty of women remain dissatisfied with the inconveniences and risks that come with the choices at hand. Some experience weight gain, acne, or nasty mood swings, or worry about the risk of stroke that can come with hormone-based pills. Others balk at the often-painful placement process for IUDs. Manually inserting a device into the lower abdomen probably wouldn’t be acceptable in other contexts without anesthesia, and yet, for women’s contraception, “we’ve socialized that into something acceptable,” Brian Nguyen, an ob-gyn and contraception researcher at the University of Southern California, told me. Nonhormonal methods such as condoms, diaphragms, and spermicide are easy to come by, but generally less effective than hormonal ones. They can also come with their own side effects. And women could certainly benefit from a greater variety of on-demand methods, Vahdat told me—contraception for when you have sex, “not just in case you have sex”—that would save them the trouble of weathering side effects all month, year, or decade long.

Over the years, some researchers have argued that significant inconveniences and side effects are acceptable for female contraception. Women, after all, are weighing those costs against pregnancy, itself a risky condition that can come with life-threatening complications; men, meanwhile, take contraception to prevent pregnancy in someone else. I asked Vahdat whether the typical side-effect profile of currently available female contraceptives would pass muster in any of the male methods in trials. “Based on history,” she told me, “I think that it would not.” Several other experts agreed. In 2011, a worldwide trial for an injectable hormonal contraceptive for men was halted when an independent safety-review committee determined that the drug’s side effects “outweighed the potential benefits.” The side effects in question included mood swings and depression, both of which are frequently experienced by women on birth control. And yet, most of the participants who stuck with the study said that they wanted to keep using the injection. In recent years, Nguyen has heard more and more of the men in contraceptive trials cite their female partners’ negative experiences with birth control as reason for their participation. “Many think of risk to their partner as a risk themselves,” he said.

[Read: The different stakes of male and female birth control]

Still, the strict standards for the tolerability of male birth control could raise the floor for female methods too. Such crossover advances are already in the works. Researchers took care to formulate the topical contraceptive for men with a dose of natural testosterone, alongside progestin, the active ingredient that halts sperm production; the idea, experts told me, is to better recapitulate what’s naturally seen in men’s bodies, to minimize unnecessary side effects. Many female hormonal contraceptives, meanwhile, rely on a synthetic compound called ethinylestradiol that incompletely mimics the estrogen women’s bodies make—and appears to raise the risk of blood clots. The Population Council is now working on another vaginal ring that replaces ethinylestradiol with hormones better matched to female biology.

Other conveniences may be trickier to translate. For example, researchers hope to someday offer men a more easily reversible vasectomy, in which a dissolvable or removable hydrogel is inserted into the vas deferens. But experts told me that temporarily stopping up the fallopian tubes is simply harder. Plus, whereas sperm are churned out constantly, eggs are released for fertilization on a cycle that can be tricky to measure and predict—which can make side effects frustratingly tough to control too, Nguyen told me. Targeted interventions are also more easily delivered to the testes than the ovaries. And their success is easier to verify: Men have long been able to check their own sperm count with a device that’s similar to an at-home COVID test, but no parallel exists for women, Wang told me. And because sperm take months to produce, male hormonal contraceptives might be more forgiving to users who miss a day of treatment—unlike many pills designed for women, which tend to be less flexible, Mitchell Creinin, a contraceptive researcher at UC Davis Health, told me.

[Read: A vaccine for birth control?]

The difficulty of wrangling eggs, though, doesn’t have to mean limiting options for women. Conception can’t happen unless egg and sperm actually meet—which means that just about any drug designed to waylay the functionality or motility of sperm could play a role in the female reproductive tract. The options go way beyond spermicide: The Population Council is working on a product that will modify the vagina’s acidity to stop sperm from swimming properly, Sitruk-Ware told me. And Deborah Anderson, an immunologist and reproductive-health researcher at Boston University, has been working on a dissolvable film imbued with sperm-blocking antibodies that can be placed into the vagina before sex, and seem to persist at high enough levels to provide contraception for 24 to 48 hours, she told me. A couple of drugs being trialed for men could even someday be marketed to women in some form—among them, a sperm-motility-blocking drug that, experts told me, might be deployable in the female reproductive tract too.

With all the attention now being paid to men’s contraceptive preferences, some researchers worry that women’s needs will fall even further to the wayside. Jeffrey Jensen, a contraception researcher at Oregon Health & Science University, told me that even as grants for male methods continue to be green-lighted, his team has had to pause work on some female-contraceptive projects because of lack of funding in recent years. “Policy makers think that we’ve checked the box and that we can move on,” he said. And Sitruk-Ware said that, although researchers had at one point started developing a topical contraceptive gel for women, “donors were more interested in the gel for men.”

Still, the arrival of male contraception is unlikely to dampen women’s enthusiasm for using their own methods, Allison Merz, an ob-gyn at UC San Francisco, told me. If anything, when those ultrasafe, ultra-effective products for men come to market, they’ll ignite more discussions over female contraception—and inspire more questions about why convenience and tolerability weren’t prioritized for women from the start.