Does exposure to folate antagonists affect pregnancy outcome?
An observational study suggests that maternal exposure to folate antagonists increases the risk of some adverse pregnancy outcomes, however an accompanying Commentary concludes that weaknesses in the study mean that it should not be used to inform practice. Maternal exposure to drugs that affect folate metabolism could feasibly affect pregnancy outcome, and there are indications that significant proportions of women of reproductive age may receive one of these drugs in any one year. The authors of this retrospective population-based cohort study aimed to use data from a Canadian healthcare administrative database to examine use of folate antagonists and placenta-mediated adverse pregnancy outcomes. They identified all pregnant women with a singleton birth (both live births and stillbirths) in Saskatchewan from January 1980 to December 2000 inclusive; information on drugs was not available for part of this period, or for the 18% of the women who were of Native status. Women who had rece
