Effect of antenatal betamethasone administration on Doppler velocimetry of fetal and uteroplacental vessels: a prospective study

Objectives: To examine the effect of antenatal betamethasone administration on Doppler parameters of fetal and uteroplacental circulation. Methods: Seventy-six singleton pregnancies that received betamethasone therapy were prospectively evaluated. Doppler measurements of pulsatility indices (PI) in fetal umbilical artery (UA), middle cerebral artery (MCA), ductus venosus and maternal uterine arteries were performed before (0 h) and 24, 48, 72 and 96 h after the first dose of betamethasone. Women with positive end-diastolic flow (EDF) in UA and those with absent or reversed EDF in UA were evaluated separately. Results: Fifty-two women with EDF in UA and 24 women with absent or reversed flow in UA were examined. Administration of maternal betamethasone was followed by a significant decrease in the PI of the MCA at 24 h (P<0.05). Additionally, return of absent to positive, reversed to absent or from reversed to positive diastolic flow in UA was detected within 24 h in 19 (79.2%) fetuses with absent or reversed UA-EDF. All alterations were transient and maintained up to 72 h. Conclusions: Antenatal administration of betamethasone is associated with significant but transient changes in the fetal blood flow. Hence, intensive surveillance of fetuses with Doppler ultrasonography is warranted following betamethasone therapy.