Enzyme-Inducing AEDs & Neonatal Bleeding
Because of case reports that maternal use of hepatic enzyme-inducing anti-seizure medications (AEDs) during pregnancy may increase the risk of neonatal bleeding, vitamin K1 has been widely recommended. However, there have been no studies of the incidence of this complication until recently.
Doctors from the Department of Obstetrics and Gynecology, at the Helsinki University Central Hospital and the Division of Pharmacology and Toxicology, Department of Pharmacy, University of Helsinki (Helsinki, Finland) sought to assess the occurrence of bleeding complications in newborns exposed to maternal enzyme-inducing AEDs in utero.
The researchers followed 662 pregnancies in women with epilepsy who used enzyme-inducing AEDs. (Controls included 1,324 pregnancies in women without epilepsy [1,334 children] matched for maternal age, parity, number of foetuses, and delivery date. None of the mothers received vitamin K1 during pregnancy, but all infants received 1 mg intramuscularly at birth.)
Of the 667 neonates, 463 were exposed in utero to carbamazepine, 212 to phenytoin, 44 to phenobarbital, 11 to primidone and 7 to oxcarbazepine. The researchers observed a bleeding complication in 5 (0.7%) of the offspring exposed to maternal enzyme-inducing AEDs and in 5 (0.4%) in the controls. However, after logistic regression analysis, bleeding was linked with birth at less than 32 weeks of gestation and with alcohol abuse but not with exposure to enzyme-inducing AEDs.
The researchers conclude that these data do not support the hypothesis that maternal enzyme-inducing AEDs increase risk for bleeding in offspring. However, administration during pregnancy of vitamin K to women receiving enzyme-inducing AEDs may still be needed in selected cases.
Sources
Neurology 2002;58:549-553. "Enzyme-inducing antiepileptic drugs in pregnancy and the risk of bleeding in the neonate"
http://www.neurology.org/cgi/content/abstract/58/4/549
