Preexisting illness, fetal malformation, and seizure control rates in pregnant women with epilepsy.

Data from 2182 pregnancies in the Australian Register of antiepileptic drugs in pregnancy that were followed to term, with 1965 followed for another year, were analyzed to ascertain whether preexisting illness influenced i. the hazard of fetal malformations, and ii. seizure control during pregnancy. Fetal malformation occurred in 74 of the 842 pregnancies associated with preexisting illness (8.8%) and in 84 of the 1340 comparator pregnancies (6.27%), Relative Risk (R.R.) = 1.402 (95% Confidence Interval (C.I.) = 1.038, 1.893). Logistic regression showed statistically significant effects of preexisting maternal drug-treated psychiatric illness, untreated psychiatric illness, and use of citalopram, carbamazepine, valproate, and topiramate in increasing hazard of fetal malformation. Preexisting nonpsychiatric illness and other antiepileptic drugs and drugs prescribed for psychiatric illness, mainly antidepressants, had no such effect. Seizures occurred during 405 of the 842 pregnancies associated with preexisting illness, and during 593 of 1340 comparison pregnancies (48.1% v 44.3%; R.R. = 1.087; 95% C.I. = 0.991, 1.192). There were no statistically significant relationships between preexisting nonpsychiatric and psychiatric illnesses separately and seizure control during pregnancy. Thus, apart from consequences of antiepileptic drug exposure, preexisting maternal psychiatric illness, in its own right, or when treated with citalopram, appears to be associated with increased hazards of fetal malformation.