New study suggests that acetaminophen (Tylenol) during pregnancy is associated with a lower risk of certain birth defects, particularly those linked with fevers.
It is presumed that women who used acetaminophen (which is considered compatible with pregnancy) to reduce fevers during pregnancy might have protected them from certain birth defects.
Reference: Feldkamp ML et al. Acetaminophen use in pregnancy and risk of birth defects: Findings from the National Birth Defects Prevention Study. Obstet Gynecol 2010 Jan; 115:109.