by Carolyn Moynihan
Women who get pregnant within a few weeks of taking birth control pills seem much more likely to have low-weight or premature babies, a new Canadian study indicates. The study does not definitively prove a cause and effect relationship and needs to be confirmed by more research, says lead investigator Xi-Kuan Chen, an epidemiologist at the University of Ottawa. However, babies with low birth weight or who are born prematurely are a growing problem and the cause is not always clear.
The researchers used comprehensive Canadian databases to distinguish three groups of women using oral contraceptives: those who had taken them within 30 days, 31-60 days, and 61-90 days of their last period before getting pregnant -- 1500 in all. They were compared to 6100 women who had not used birth control pills for at least a year before they gave birth.