Abstracts

Pregnancy registries have been developed to provide an early signal of an increased frequency of major malformations associated with prenatal exposure to the products monitored by the registry. The North American Antiepileptic Drug (AED) Pregnancy Registry is an ongoing surveillance system of pregnant women exposed to AEDs. By May 6, 2004, the Registry had enrolled 3,633 women from the United States and Canada since its inception seven years ago. The eligible woman must call the toll-free number. She is interviewed at enrollment, at 7 months gestation, and postpartum. Medical records were obtained about the mother[apos]s medical history and the normal or abnormal findings in the infant. The protocol and criteria for the release of findings were established prospectively by a non-industry external Scientific Advisory Committee. The inform consent to be read and signed by each woman who enrolls in the Registry was reviewed and approved by the Human Studies Committee of the Massachusetts General Hospital in Boston, where the Registry is based. The risks due to maternal exposure to two AEDs as monotherapy have recently been released: assuming a background prevalence of major nonsyndromic congenital anomalies of 1.62%, the relative risk to having an affected offspring for valproic acid-exposed women was 5.0 (95% CI: 2.9-8.6) and 3.8 (95% CI 1.7-9.0) for women exposed to phenobarbital. The results from this hospital-based pregnancy registry indicate that prenatal exposure to monotherapy valproic acid or phenobarbital is associated with a significantly increased risk for fetal abnormalities. (Supported by Abbott, Elan, GlaxoSmithKline, Novartis, Ortho-McNeil and Pfizer.)