Antenatal corticosteroid therapy: a comparative study of dexamethasone and betamethasone effects on fetal Doppler flow velocity waveforms

Abstract

Objective: To compare the effects of antenatal administration of dexamethasone and betamethasone, used in two different regimens, on fetal Doppler flow velocities.

Study design: Sixty-seven women at risk for preterm delivery received course of corticosteroids by means of a computer-generated randomization table. The Doppler examination of the pulsatility index (PI) of the umbilical artery (UA), the middle cerebral artery (MCA) and the middle cerebral artery/umbilical artery PI ratio (MCA PI/UA PI) were performed before treatment, 24 and 72 h after the first dose of corticosteroids. The SAS system was used to perform statistical analysis.

Results: No significant change was observed in UA PI through dexamethasone therapy. In MCA there was a significant decrease in PI at 72 h (2+/-0.43 before and 1.68+/-0.31 after, p=0.0001). Similarly a significant decrease in MCA PI/UA PI ratio was noted (2.09+/-0.51 before and 1.83+/-0.4 after, p=0.0137). No significant changes were observed in UA PI, MCA PI and MCA PI/UA PI ratio during betamethasone treatment.

Conclusions: Our results indicate significant decrease in fetal middle cerebral artery impedance at 72 h after maternal administration of the first dose of dexamethasone. Effects of dexamethasone on fetal brain warrants further research.