Expert explains why men’s birth control options are so limited: ScienceAlert

In the wake of the overturning of Roe v. Wade, developing more contraceptive options for everyone becomes even more important.

Women and people who can become pregnant have a variety of effective birth control methods available, including oral pills, patches, injections, implants, vaginal rings, IUDs, and sterilization.

But for men and people who produce sperm, the options were limited. Two options, withdrawal and condoms, both have high failure rates. Withdrawal has a failure rate of about 20 percent. Condoms only have a 2 percent failure rate when used correctly, but that rate rises to 13 percent based on how people typically use them.

Vasectomies have a failure rate of less than 1 percent, but require minimally invasive surgery and are considered a permanent method of contraception. Neither vasectomies nor withdrawal protect against sexually transmitted infections.

There hasn’t been a new form of birth control for men since the introduction of the “no scalpel vasectomy” in the 1980s. I, along with my team, have been developing methods of male contraception since the 1970s.

I believe that new safe, reversible and affordable contraceptive options can help men participate and share contraceptive responsibilities with their partners and reduce the rate of unintended pregnancies.

Taking responsibility for family planning

A 2017 survey of 1,500 men ages 18 to 44 found that more than 80 percent wanted to prevent their partner from getting pregnant and felt they had joint or sole responsibility for birth control.

Men who are dissatisfied with condoms are more likely to either use withdrawal as a form of birth control or never use contraception. Of those dissatisfied with condoms, however, 87% are interested in new methods of male contraception.

This translates to approximately 17 million men in the US seeking new contraceptive methods to prevent unintended pregnancies.

Similarly, a 2002 survey of more than 9,000 men in nine countries on four continents found that more than 55 percent would be willing to use a new method of male birth control.

Significantly, a 2000 survey across three continents found that 98 percent of women would trust their partner to use a male method of birth control.

Barriers to male contraception

The intense interest in a new male contraceptive raises the question of why there have been no new methods of male birth control since the 1980s.

The development of male contraception has been supported primarily by governmental and non-governmental organizations, including the World Health Organization working with academic medical centers.

However, these agencies often lack a drug development infrastructure comparable to pharmaceutical companies, with programs typically run by only a small staff assisted by clinical research organizations. Limited financial resources further slow growth.

Lack of interest from pharmaceutical companies may also play a role in preventing the development of male contraception, and there are several possible reasons why the drug industry avoids male birth control.

One reason involves weighing development costs against uncertainties about the potential market. Other reasons include uncertainties about who would administer these drugs and unclear regulatory requirements for male contraceptive methods to receive FDA approval. Companies may also be concerned about liability in the event of pregnancy.

New methods in development

Researchers are currently looking at several different methods of male contraception.

Hormonal methods are usually taken as a gel applied to the skin, an injection into the muscle, or a pill taken by mouth. These methods usually contain testosterone and progestin. The progestin suppresses two pituitary hormones that control the testicles, the organs that produce sperm.

While the testes require high concentrations of testosterone to produce sperm, testosterone is usually included in hormonal regimens to ensure that there is an adequate level of the hormone for other bodily functions.

Conversely, taking testosterone can also help suppress sperm production because increasing circulating testosterone levels above a certain level suppresses the same two pituitary hormones. The addition of a progestin further enhances the suppression of sperm production.

The hormonal contraceptive candidate furthest along in development is currently in an ongoing Phase II clinical study that has enrolled over 400 couples on four continents. I served as the principal investigator of this trial at the Lundquist Institute.

The results of the study, funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the Population Council, have been promising so far with few side effects and couples finding the gel acceptable to use.

My team and I are also developing drugs that work like testosterone and progestin, but in a single compound. These drugs are currently undergoing early human trials as a daily oral pill or long-acting injection.

Non-hormonal methods usually involve drugs that specifically target the sperm-producing organs to reduce sperm concentration or function. Nonhormonal drugs show efficacy in animal models, but preclinical toxicology results are required before clinical studies can be initiated to demonstrate safety, tolerability, and efficacy in humans. Some of these methods are working toward phase one clinical trials.

Another non-hormonal method involves the reversible blocking of the vas deferens, an organ that transports sperm for ejaculation. Studies funded by the Male Contraception Initiative and the Parsemus Foundation are testing hydrogels, a type of water-retaining polymer that prevents sperm from traveling through the vas deferens.

People are ready for new methods of contraception. I believe that collaboration between academia, government, non-profit and pharmaceutical sectors can help provide new birth control methods that are safe, reversible, acceptable and accessible to all.

Christina Chung-Lun Wang, Physician/Researcher at the Lundquist Institute at Harbor-UCLA Medical Center and Professor of Medicine at the David Geffen School of Medicine, University of California, Los Angeles.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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