The Future of Birth Control

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You’ve heard of the pill, IUDs (intrauterine devices), and barrier methods like condoms, of course. But researchers are working on some exciting new options for birth control—some of which have already been approved by the U.S. Food and Drug Administration. Read on to learn more.

Phexxi is a vaginal gel that you insert less than an hour before vaginal sex and lasts up to an hour. It works by lowering the pH of your vagina, which makes it hard for sperm to move and find an egg. In the phase 3 clinical trial to test Phexxi, which was published in 2020 in  the journal Contraception: X, researchers found that Phexxi was 86.3 percent effective at preventing pregnancy. [1] If used perfectly, it’s likely that the gel would be even more successful. A few great things about Phexxi are that it is not hormonal and that you don’t have to remember to take it every day like a pill—you just have to use it right before sex. It comes in a pack of twelve doses and is available by prescription from your doctor or nurse practitioner.

One birth control method that is still under development is a non-hormonal male pill. In a study published in Nature Communications in February 2021, Wei Yan, a physician and researcher affiliated with UCLA and the University of Nevada, Reno, and colleagues showed that a chemical isolated from an herb used in traditional Chinese medicine could be a promising male contraceptive. [2]

The researchers gave the chemical, which they named triptonide, to male mice and monkeys. They found that triptonide gave the mice deformed sperm that did not swim as well as typical sperm after just four weeks of taking it. In addition to being deformed and bad at swimming, these sperm were not capable of fertilizing an egg, either naturally or via in vitro fertilization, suggesting that taking triptonide induces sterility. Importantly, this sterility was reversible. When the mice stopped taking the drug, their sperm recovered within months.

Yan and colleagues also tested the drug in monkeys for nearly two and a half years. They found that triptonide had a similar effect on monkey sperm, causing deformation and defects in swimming, that were reversible. After the monkeys had taken the drug for years, they were able to then father children. Importantly, the monkeys had no obvious side effects over the more than two-year period that they took the triptonide. Because this strategy has so far only been tested in animals, the next steps will be to examine safety and efficacy in people.

Another birth control method that is currently still in early stages of development is an antibody that binds and immobilizes sperm. Antibodies are a natural part of our immune system, the system of the body responsible for fighting invaders, such as viruses and bacteria, that cause diseases. Researchers at the University of North Carolina at Chapel Hill showed in a paper published in August 2021 that they could immobilize sperm in the reproductive tract of female animals using an antibody, which they engineered.

The antibody is designed to stick part of sperm cells. Once the antibodies glom on to the sperm, the sperm clump together, rendering them ineffective at swimming and thus finding an egg to fertilize. The authors of the antibody paper have formed a company through which they hope to commercialize the technology, so that it can be used widely, perhaps as a special vaginal film with tons of these sperm binding antibodies stuck to it. The idea is that you could just insert this film before having sex and then it will make it very hard for you to get pregnant.

While some of these methods might seem like a pipe dream, the call for innovative and exciting new ways to prevent pregnancy is only getting louder. We can only hope that the scientists working in this area answer that call sooner rather than later.

  1. A. Thomas et al., “A novel vaginal pH regulator: results from the phase 3 AMPOWER contraception clinical trial,” Contraception: X, 2020.
  2. Chang et al., “Triptonide is a reversible non-hormonal male contraceptive agent in mice and non-human primates.” Nature Communications, 2021.
  3. Shrestha et al., “Engineering sperm-binding IgG antibodies for the development of an effective nonhormonal female contraception,” Science Translational Medicine, 2021.
Abby Olena
Dr. Abby Olena has a PhD in Biological Sciences from Vanderbilt University. She lives with her husband and children in North Carolina, where she writes about science and parenting, produces a conversational podcast, and teaches prenatal yoga.

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