Being infected with a species of parasitic worm may increase female fertility, according to new research.
The scientists studied the Tsimane women of Bolivia, famous for their high fertility rates.
On average, the Tsimane women have 10 children in their lifetimes, but some of the women are more fertile than others. University of California at Santa Barbara collected information on nearly 1,000 women from the community over nine years and discovered it may have to do with being infected with a parasitic worm.
Writing in the journal Science, researchers suggested the worm could be changing the immune system, making it easier for the host to become pregnant. The findings could lead to new fertility-enhancing medications.
About 70 percent of women in the community have the parasitic worm infection. Up to one third of the world’s population also lives with such infection.
While the worm studied – Ascaris lumbricoides, a type of roundworm – increased fertility, hookworms actually decreased it.
Women who had the roundworm had as many as 12 children, while those who had the hookworm instead had a number closer to just seven.
According to researchers, women are more likely to become pregnant as their immune systems become less likely to reject the fetus after being infected.
Prof Aaron Blackwell, one of the researchers , said:
The effects are unexpectedly large. 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.
He also said that the idea of using a worm as part of a fertility treatment is “an intriguing possibility,” though he warned more research was necessary before he recommended anyone try using the worm.
He concluded: “Whilst I wouldn’t want to suggest that women try and become infected with roundworms as a way of increasing their fertility, further studies of the immunology of women who do have the parasite could ultimately lead to new and novel fertility enhancing drugs.”