Effects of antenatal corticosteroids on fetal hemodynamics: a longitudinal study.

Objective: To study the effect of antenatal corticosteroid administration on fetal hemodynamics using longitudinal analysis of Doppler waveforms in the umbilical artery (UA) and middle cerebral artery (MCA).

Materials and methods: This was a retrospective study that included 30 fetuses at risk for preterm birth. Twenty-eight pregnant women were treated with betamethasone for fetal lung maturation. Doppler examinations of the UA and MCA were performed once before and three or eight times after corticosteroid administration. We used a Bayesian hierarchical linear model. Reference ranges were constructed, and associations between variables (gestational age and pre-eclampsia) were tested.

Results: The mean maternal age, gestational age at betamethasone administration, and gestational age at delivery were 32.6 ± 5.89 years, 30.2 ± 2.59 weeks, and 32.9 ± 3.42 weeks, respectively. On UA Doppler, there was a significant decrease in the pulsatility index (PI) after corticosteroid administration, with a mean of 0.1147 (credibility interval: 0.03687-0.191) in three observations and a median of 0.1437 (credibility interval: 0.02509-0.2627) in eight observations. However, there was no significant change in the Doppler MCA PI, regardless of gestational age and the presence or absence of pre-eclampsia.

Conclusion: Although antenatal corticosteroid administration induced a significant decrease in the Doppler UA PI, we observed no change in the cerebral vasculature.