Earlier studies have shown that a woman’s body makes adjustments to its immune system defenses during pregnancy, and that allows the fetus to develop and function within the body.

New research from a population in Bolivia is now showing that a body with an infection of a parasitic worm can also have an influence on the body, and women with a certain type of worm infection are more likely to become pregnant, according to a UPI story.

Researchers from the University of California-Santa Barbara investigated the effects of roundworm and hookworm infections on women from the Tsimane population in Bolivia, and found the different infections have different effects.

The research team looked at data collected over a nine-year period, on 986 Tsimane women, about 70 percent of which had been infected with either the roundworm or the hookworm.  Those are the most common forms of the parasite.

Normally, Tsimane women are totally unaware they have contracted the parasite, mainly because in most cases there are no symptoms present, but the researchers found they all had an increased level of immune response.

The data reveals that among Tsimane women, who average about nine children over their lifetimes, those with a hookworm infection were only averaging six, three fewer, and those infected with roundworm averaged two more than normal.

Lead author of the study Aaron Blackwell said the team believes that effects relate to the balance of immune responses produced by the different worms, which affects the likelihood of conceiving.  He adds that immune changes in the body make it more or less friendly toward becoming pregnant.

But no one is recommending getting a roundworm infection if you are having difficulty getting pregnant.  The results are preliminary to begin with, and only show an association and not a cause-and-effect relationship, and some roundworm infections can lead to shortness of breath, fever, anemia, and in some cases, even death.

These new findings could lead to a better understanding of the role the immune system plays in conception, and could lead to new types of fertility treatments in the future.

The findings of this new study was published in the journal Science.