Birth weight in offspring of women with epilepsy.

Abstract

Epilepsy is the most common neurologic disorder in pregnant women. The prevalence is 0.2-0.6 percent (1-3). Research on epilepsy and pregnancy has mainly been on treatment with antiepileptic drugs and the risk of congenital malformations (4), and a number of studies have demonstrated an increased risk (5-8). We know less about the effect of epilepsy and antiepileptic drug treatment on preterm delivery and intrauterine growth restriction. Both of these events are frequent, and both are important risk factors for neonatal mortality (9, 10) and for childhood morbidity such as cerebral palsy and cognitive dysfunction (11, 12). Furthermore, the consequences of intrauterine growth restriction seem to go far beyond childhood (13). Until now, the studies on the association between epilepsy and preterm delivery and intrauterine growth restriction have led to no overall conclusions. Preterm delivery is defined as delivery before 37 completed weeks of gestation (14). Gestational age may be estimated from the last menstrual period, from ultrasound scanning, or from a postnatal assessment (15). Estimates from the last menstrual period may be biased because the incidences of oral contraceptive failure and vaginal bleeding in pregnancy are increased in women with epilepsy (16, 17). On the other hand, the use of ultrasound may overestimate the risk of preterm delivery in women with epilepsy if early fetal growth restriction is more pronounced in women with epilepsy than in healthy women (18, 19). The most commonly used proxy measure for intrauterine growth restriction is small for gestational age, defined by birth weight below the 10th percentile for the specific gestational age at birth. The 10th percentile is often derived from cross-sectional birth weight for gestational age standards, but standard percentiles vary up to 500 g for term deliveries and may not be specific for gender or race (20). Being small for gestational age may therefore reflect a