Source
Department of Obstetrics, Gynecology, and Neonatal Care, Hôpital Jeanne de Flandre, University of Lille, France. d-subtil@chru-lille.fr
Abstract
OBJECTIVE:
The purpose of this study was to evaluate the role of different formulations and different administration kinetics of antenatal corticosteroid therapy on fetal heart rate.
STUDY DESIGN:
One hundred five patients who were at high risk for preterm delivery were assigned randomly to receive two injections of betamethasone acetate + phosphate, four injections of betamethasone phosphate, or four injections of dexamethasone phosphate. Computerized fetal heart rate was recorded daily through day 4.
RESULTS:
The three formulations did not differ in their effect on fetal heart rate, which varied significantly as a function of the time of injection. During treatment (day 0-day 1), fetal heart rate variability increased (+9%, P <.05), as did the number of fetal movements felt by the mother (+60% at day 0, P <.001). After treatment (day 2-day 3), variability fell significantly (-14%, P <.01), as did accelerations (-35% at day 2, P <.01). No modifications were still detectable on day 4.
CONCLUSION:
Antenatal corticotherapy is responsible for two different phases of fetal heart rate modifications that do not vary according to the corticosteroid or the dosage regimen.