Effect of betamethasone on computerized cardiotocographic parameters in preterm growth-restricted fetuses with and without cerebral vasodilation.

OBJECTIVE: To verify the effects of maternal corticosteroid administration on fetal behavior and heart rate variation using computerized cardiotocography (cCTG) in a selected group of growth retarded fetuses. STUDY DESIGN: Fifty singleton pregnancies complicated by fetal growth restriction were enrolled in the study before 34 weeks of gestation. All of them received two intramuscular injections of 12 mg of betamethasone 24 h apart. Fetal heart rate was recorded by cCTG before the first injection, and every 24 h for the 3 days following the end of the treatment. After Doppler evaluation of cerebral circulation, fetuses were divided into a group with and a group without signs of cerebral vasodilation. Basal heart rate, short- and long-term variation, percentage of time spent in high variability, fetal movements and percentage of small accelerations were evaluated. RESULTS: Basal fetal heart rate did not show significant changes. Short-term variation and percentage of time spent in high variability significantly decreased in fetuses with but not in fetuses without vasodilation. Long-term variation and fetal movements significantly decreased in both groups. CONCLUSIONS: Maternal administration of betamethasone in growth-retarded fetuses with cerebral vasodilation is associated with significant but transitory modifications of fetal heart rate variation.