A case control study on the association between maternal epilepsy, 
anticonvulsants use during pregnancy and birth defects was carried out in the 
Italian Multicentric Registry of Birth Defects (IPIMC). In the period 1980-1983, 
7,607 malformed babies out of 439,717 total births (still + live) were 
registered. Fourty-one malformed babies with maternal epilepsy were identified 
(5.39 X 1,000). The overall relative risk of having a malformed baby among 
pregnant epileptic women was 1.87. Spina Bifida, Congenital Heart Defects, 
Clefts, Diaphragmatic Hernia and Trisomy 18 were more frequent than expected 
among babies with maternal epilepsy. The different therapeutic regimens were 
also tested to identify the possible independent teratogenic effect of 
anticonvulsants. A statistically significant association between Spina Bifida 
and Valproic Acid (odds ratio 22.7; Fisher p value = 0.0364) was observed: no 
other anticonvulsant tested showed any association with any type of 
malformation.