Congenital malformations in infants exposed to antiepileptic medications in utero at Boston Medical Center from 2003 to 2010.

OBJECTIVE: The aim of this study was to determine the frequency of association of major congenital malformations in pregnancy in women exposed to antiepileptic drugs (AEDs) in an inner city population.

BACKGROUND: Approximately 0.3-0.5% of all pregnancies involve women with epilepsy. The risk of congenital malformations associated with AED therapy has been well documented, ranging from 2 to 10% as compared to a rate of 3% in the general population. However, the risk of these occurring in a higher risk population, such as an inner city tertiary care center, with multiple comorbidities is not as well known.

DESIGN/METHODS: Using the Boston Medical Center Database between the years 2003 and 2010, a list of all infants born with major congenital malformations (MCMs) to mothers on AEDs was compiled. Major congenital malformations were defined as cleft lip and/or palate, ventricular or atrial septal defect, other cardiac malformations, and urogenital defects. During pregnancy, AED exposure including serum levels, other medication exposures, breakthrough seizure frequency, positive toxicology tests, and other maternal comorbidities were also analyzed.

RESULTS: Of 17,246 live births between 2003 and 2010, 330 of those births demonstrated a MCM (malformation rate of 1.91%). Of those births, 64 mothers had epilepsy and were exposed to AED therapy during pregnancy, accounting for 0.37% of all births during this time period. Overall, three pregnancies in women with epilepsy resulted in a baby with a MCM, accounting for a 4.7% malformation rate in this patient population. In mothers on AEDs for other indications, the MCM rate was slightly higher, 5.0%, and in women on benzodiazepine monotherapy during pregnancy, the rate was quite high, 10.6%.