Can a Parasitic Worm Boost Female Fertility?

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The women from Tsimane, Bolivia are often revered as the most fertile in the entire world. On average these women have ten children each during their lifetime, but there are some who have even more children than that. It makes one wonder how these women have come to be so fertile?

Fertile Women of Bolivia

Researchers from the University of California gathered information on nearly 1,000 women in the Tsimane community for a period of nine years. The team discovered that it could be related to something fairly shocking: parasitic worm infestation.

It was discovered that females who were chronically infected with roundworm had as many as twelve children. In contrast, females who had successive hookworm infections saw their birth rates decrease to an average of seven children.

Lead author of the study, Aaron Blackwell and his team wrote in the journal Science theorizing that the effects “may be related to the balance of immune responses that the different worms induce.”

Women who were infected with roundworm recorded earlier first-time births and shortened time spans between the next births. However, women who were infected with hookworms experienced a delayed first pregnancy and extended periods of time between subsequent births. Blackwell told the BBC that the immune changes in a female’s body may make it more susceptible to pregnancy.

Is this a Better Alternative to IVF?

Could parasitic worm infestation work better than IVF? Fertility experts said the findings could result in new types of fertility treatments for women who are having trouble getting pregnant in the future. However, under no circumstances should a woman try to increase her chances of getting pregnant through intentional parasitic worm infestation.

Firstly, the results of this study are only preliminary and merely show an association rather than a definitive link and researchers are not sure of how or what mechanisms are at play. While being infected with roundworms is quite common and most cases are without symptoms, they can cause shortness of breath, anemia, and fever and in some instances it can be deadly.


More study is needed in order to find out exactly when the women of Tsimane, Bolivia experience such robust fertility. It’s not known how roundworms and hookworms infections increase fertility, nor is it known if these parasites could play any type of role in improving fertility or offering new treatment options for women struggling to conceive.


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