--- title: Parasitic Worm May Increase Women's Fertility: Study description: The researchers studied 986 Tsimane women in Bolivia for nine years. canonical: https://time.com/4121861/parasitic-worm-fertility-study/ author: Julia Zorthian article:opinion: false article:content_tier: free article:published_time: 2015-11-20T14:18:51.000Z article:modified_time: 2026-08-04T07:57:06.985Z article:section: Health og:title: Parasitic Worm May Increase Women's Fertility, Study Suggests og:description: The infection may have an effect on the immune system og:url: https://time.com/4121861/parasitic-worm-fertility-study/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltbcbbc1c7153a17b5/6988721c5f570f3519b1e72a/ascaris-lumbricoides.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 og:image:width: 4625 og:image:height: 2602 og:image:alt: 158680049 og:type: article twitter:card: summary_large_image twitter:title: Parasitic Worm May Increase Women's Fertility, Study Suggests twitter:description: The infection may have an effect on the immune system twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltbcbbc1c7153a17b5/6988721c5f570f3519b1e72a/ascaris-lumbricoides.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 ---  # Parasitic Worm May Increase Women's Fertility, Study Suggests > Sponsored content. 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Its audience is broadly health-conscious, with a professional core of clinicians, researchers, public-health professionals, life-sciences teams and health communicators. ### Sources * TIME Newsletters: [time.com/newsletters](/c/time-nl-health-2026q3/newsletters?i=1919a0ad-efea-4a10-9f31-bbe4564ae88f&cr=time-nl-health-2026q3-v1) ## Video: After 2 Rejections, FDA Approves Drug Dubbed 'Female Viagra' [Watch (HLS stream): After 2 Rejections, FDA Approves Drug Dubbed 'Female Viagra'](https://cdn.jwplayer.com/manifests/Zs5thHzC.m3u8) (1:07)  _Published 2015-08-19. The FDA approved Addyi, a drug whose maker claims it helps raise sexual desire in women. But it's been a long and controversial process._  by [Julia Zorthian](https://time.com/author/julia-zorthian/)  ## Julia Zorthian Nov 20, 2015 2:18 PM UTC  Ascaris Lumbricoides unfertilized eggs under a microscope. Ascaris Lumbricoides unfertilized eggs under a microscope. Getty Images  by [Julia Zorthian](https://time.com/author/julia-zorthian/)  ## Julia Zorthian Nov 20, 2015 2:18 PM UTC Women who are infected with a certain parasitic worm may be more likely to become pregnant, according to a new study. The study, [published in ](http://www.sciencemag.org/content/350/6263/970)[_Science_](http://www.sciencemag.org/content/350/6263/970)on Friday, studied 986 Tsimane women in Bolivia for nine years, and found that women infected with the roundworm species _scaris lumbricoides_ had about two more children than women without the worm (Tsimane women have an average of 10 children in general). The researchers noted that the infection is associated with shortened intervals between births, and with earlier first pregnancies. “We think the effects we see are probably due to these infections altering women’s immune systems, such that they become more or less friendly towards a pregnancy,” University of California Santa Barbara professor Aaron Blackwell, one of the study’s authors, [told the BBC](http://www.bbc.com/news/health-34857022). The researchers suggested that a suppressed immune system due to the infection may make the body less likely to reject a fetus. Blackwell added that further research is necessary before there could be any practical use of this potential link between the roundworm infection and fertility. ## Transcript The FDA has approved a drug that's long been trumpeted as the female Viagra. The brand name is Addy and it's a non- hormonal pill that treats hypoactive sexual desire disorder in pre- menopausal women. Unlike Viagra though, the drug doesn't address a physical problem like erectile dysfunction. Instead it's thought to work on the nervous system, affecting desire itself. Addyi has been controversial for a long time. In 2010, it was rejected by the FDA. Major concerns included the benefits not being dramatic enough, the testing methods not being thorough enough, and a lack of consensus on the low- libido diagnosis it claims to treat. In my clinical practice of 15 years in general internal medicine, I've never met a woman That fulfills the formal diagnostic criteria for this disorder. Other critics have accused the drug maker of treating normal levels of sexual desire like the disease and of misusing feminist rhetoric in its marketing, while the company frames the drug as a breakthrough for women. I think this is absolutely an evolution in the female sexual revolution. 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