Research on male contraception begins to make headway: Shots

Reduction in sperm count illustration.

Condoms have been used to prevent pregnancy since medieval times, and the rubber version came on the market in the mid-1800s. Over the years they have become more effective and comfortable to use.

But it was the invention of birth control pills, followed by IUDs in the 1960s, that sparked a seismic shift in people’s ability to control reproduction. A growing range of pills, patches and implants became available to women. And yet, a stretchable sheath covering the penis remains the only medically approved form of birth control for men, aside from vasectomy.

But now researchers are investigating both hormonal and non-hormonal contraceptives for sperm carriers. The hope is that couples will begin to view birth control more as a shared responsibility.

“We want to create a menu of options for men that is similar to what women have available to them,” said Stephanie Page, a researcher and endocrinologist at the University of Washington.

(Note: The studies mentioned here are mostly conducted on cisgender men between the ages of 18 and 50, so this story refers to the drugs as “male birth control” and their target demographic as “males” or “males,” although people of other genders can produce sperm.)

Hormonal methods are getting renewed scrutiny

The lab of Dr. Page, along with researchers at 15 other locations around the world, is conducting a clinical trial testing a topical gel that a man applies to his shoulders every day. The gel contains synthetic hormones – a combination of testosterone and progestogen – that signal the brain to lower testosterone levels in the body. And since testosterone is needed for sperm to mature, the testes produce less and less sperm.

The study of dr. Page enrolls couples – nearly 450 of them worldwide. If the woman is also involved, it means “she’s taking consent just as much as he is, and they’re really both participants,” says Page.

The sea trial will take place in phases. In the first phase, the man applies the gel every day, but the couple still uses a different form of contraception when they have intercourse. During this phase, researchers periodically check the man’s sperm count. If the number is low enough to prevent pregnancy, the couple enters the second phase: they stop using other methods of contraception, while the man continues to use the gel daily.

In the third and final stage, the man stops using the gel and researchers start checking his sperm count again. Researchers hope their results will show that the effect on fertility is reversible, just as women can regain their fertility when they stop taking birth control pills.

Brian Nguyen, an ob-gyn and professor at the Keck School of Medicine at the University of Southern California who also researches male birth control, says he is encouraged by what he hears from some of the men in the gel trial, especially those “who really just want to support their female partners.”

“I hear stories about how men are really tired of hearing that their partner is suffering from hormonal side effects or in some cases complications related to IUDs or implants,” he says. “And they want to do something.”

Nguyen’s lab is also working on a hormonal pill that would work similarly to the gel, and Page’s lab hopes to eventually develop an injectable hormone solution.

In the 1990s, the World Health Organization sponsored trials of male hormonal contraceptives — giving men high doses of testosterone — but those drugs never made it to market. Researchers thought they weren’t effective enough to sell, and the side effects were serious, including toxicity to the heart, liver, and kidneys, and a possible increased risk of prostate cancer.

Stephanie Page of the University of Washington says the gels and pills being tested now don’t carry the same risks.

“We’ve worked really hard to develop methods that don’t affect those other physiological parameters,” says Page, “So we don’t see any effects on kidney function, liver function and things like that.”

In terms of side effects, some participants report weight gain, changes in libido, acne or mood swings.” These, she explains, are very similar to the side effects some women experience when using female hormonal contraceptives.

Promising non-hormonal approaches

Another area of ​​research focuses on precise points in the sperm’s life cycle, including the ability to swim or to fertilize an egg. These drugs are a little more precise than hormonal drugs, says Logan Nickels, director of research at the Male Contraceptive Initiative, which supports researchers working on nonhormonal contraceptives.

“They target a very specific link in the chain of a sperm’s generation or lifespan and … if you were to break that link, there are no other bodily functions or other broad signals that you interrupt.” In other words, someone those using these methods are likely to experience little to no side effects, he says.

“The male reproductive system is really cool because there are hundreds and hundreds of links in this chain, [so] that if you knock out one of them, you’re basically getting a barren man,” says Logan.

Another non-hormonal method being tested in Australia is a gel that is injected into the vas deferens – the tube that carries sperm to the urethra in preparation for ejaculation – and blocks sperm transport. Logan says it could be a reversible alternative to a vasectomy.

Why does it take so long?

Page estimates it will be another seven to 10 years before any of these new methods can be sold. So why have women had to shoulder so much birth control responsibility for so long?

“Women carry the life-threatening burden of pregnancy,” says Page. “And so the first energy went into making sure women had control over their own reproduction.”

And, she says, developing male birth control is more complicated. Women usually release an egg or two a month. Men produce millions of sperm per day – a single ejaculation contains about 15 million to 200 million sperm per milliliter of semen. Researchers had to figure out how low the count should be to reliably prevent pregnancy. They’ve now determined that it should be less than 1 million sperm per milliliter of semen, Page says.

And the FDA’s criteria for approving contraceptives for men are vague.

The pharmaceutical industry and the FDA use data from studies to weigh the benefits and risks for the patient. But dr. Page says the risk calculation should be different in this case.

“If we think about risks, what are we protecting the man against? In the case of contraception for women, the woman is protected against the risk of pregnancy and potentially unsafe abortion. But in men, they really use contraception to protect their partner. If if we think of the man as a single unit, of course there should be no side effects and no risks. But I think we really need to move on to thinking about mating as a dyad and this is a shared risk,” she says.

Another barrier to the marketing of male contraceptives is the degree of efficacy. Female birth control implants and IUDs are 99% effective and birth control pills are 93% effective, according to Planned Parenthood. Male contraceptives may need to be just as good at preventing pregnancy to sell.

“Drug manufacturers invest millions and millions of dollars in a drug before they see a penny of profit,” says Nickels. “And so when they take those calculated risks, those calculated investments, they’re trying to make sure they’re going to see their money at the end of it,” he says.

Nickels, Page and Nguyen all expressed optimism that a male contraceptive will hit the market in the next decade, though funding could be a limiting factor.

Logan predicts that the injectable non-hormonal gel or the topical hormonal gel will be first to market.

According to Brian Nguyen, it is important for men to be better informed about what women go through in order for male contraceptives to succeed in the market.

“Men are often shielded from discussions about menstruation, pregnancy, childbirth, infertility. Most men have a sense of invulnerability because they don’t have to think about the need for contraception. And the only way to fix that is to take more and more open conversations with men about reproduction and their responsibility in a process that is not just a women’s issue.”

Women have been waiting for that mindset change for a long time. But even if it doesn’t happen right away for most heterosexual men, the freedom to skip the sheath might be motivation enough.

This episode’s audio was produced by Rebecca Ramirez, edited by Gisèle Grayson, and overseen by Abē Levine. Tre Watson was the sound engineer.

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