Parasitic worm boosted fertility in women

It turns out that the Ascaris lumbricoides – a type of roundworm – can increase a woman’s fertility.

Another fertility scientist, professor Allan Pacey at the University of Sheffield, said the results could lead to new drugs for women wanting to become pregnant.

Globally, the Tsimane women from Bolivia are often considered the most fertile with an average of 10 children during their lifetime. About 70% of the women in the population has a parasitic worm infection.

Over the span of nine years, researchers from the University of California, Santa Barbara observed the fertility rates of women who belonged to the indigenous Tsimane community in central Bolivia. They also linked the parasite to earlier first pregnancies.

Lead author Aaron Blackwell Ph.D. told the BBC that using such worms to enhance fertility is an “intriguing” possibility but he doesn’t recommend people try it until more studies are done. However, they warn that women should not try to increase their chances themselves by attempting to get a roundworm infection of their own. Between 2004 and 2013, doctors who visited the Tsimane villages gave physical exams and checked their patients’ feces for roundworms and hookworms.

Experts in the fertility field stated that these findings could improve In Vitro Fertilization (IVF) by developing new means and treatment for those women showing troubles to getting pregnant in the future.

Researchers have found that roundworm infection resulted in shorter birth intervals among Tsimane women and allowed them to have two more children on average compared to other Tsimane women. The parasites, intestinal worms belonging to the helminths family affect the timing of the women’s pregnancies.

While it’s comparatively uncommon in South America, “some populations have infection rates as high as 95 per cent”.

In the case of women with the roundworms, for example, the parasite may decrease immune response as a way of protecting the fetus that may be viewed by the immune system as a potential threat.

Women who were chronically infected with roundworm had as many 12 children.

But Prof Maizels intimates that parasites do the opposite, “growing slowly and trying to suppress the immune system”, and this is why they make vaccines less effective at lower allergy levels.

A second parasite, hookworm, was also detected in the population and has an opposite effect on its host.