A paper in the American Journal of Human Biology led by UC Santa Barbara scholars investigates the relationship between hookworms and pregnancy in indigenous Tsimane women of the Bolivian Amazon. The Tsimane are forager-farmers who live in a tropical rain forest environment, and so are exposed to many diverse pathogens — including endemic hookworm. Tsimane women also have high fertility — the average woman has nine births over her lifetime. By analyzing longitudinal data, the researchers sought to determine if there’s a tradeoff between mounting an immune response to hookworm and having a successful pregnancy.