The North American Antiepileptic Drug (AED) Pregnancy Registry is studying the effects of anticonvulsant medications in pregnancy. It was established in 1997 for pregnant women in the United States and Canada at the Massachusetts General Hospital in Boston, MA. It is the first hospital-based registry established to determine the safety of seizure medications that can be taken by women during pregnancy. We are very grateful to the 10,200 women who have enrolled so far. Our studies involve phone interviews with participating patients. No needles, no medications, and no changes to a woman's routine are required. The information they provide during the course of their pregnancy provides future support to women diagnosed with epilepsy, mood disorder or chronic pain.