Oral phenobarbital given antenatally to reduce neonatal intraventricular hemorrhage. A comparison between maternal and umbilical cord serum levels at delivery.

This investigation was undertaken to compare maternal and neonatal cord serum levels of phenobarbital given orally to mothers anticipated to deliver very low birthweight infants at risk for neonatal intraventricular hemorrhage (IVH). Fifty women anticipated to deliver between 26 and 34 weeks' gestation agreed to receive a daily oral dose of 90 mg of phenobarbital. The umbilical cord to maternal phenobarbital concentration ratio at birth was 1.05 and remained constant after the first day of maternal therapy. Cord phenobarbital concentrations increased rapidly during the first 3 days until reaching a steady state by the end of the first week of therapy. In contrast to recent promising reports using large doses of phenobarbital given parenterally shortly before delivery, lower doses of oral phenobarbital did not reach cord levels reported to be protective against IVH or therapeutic as an anticonvulsant.