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

## TL;DR

This study found that antenatal corticosteroids significantly reduce blood flow resistance in the umbilical artery but do not affect cerebral blood flow in fetuses.

## Contribution

The study provides new longitudinal evidence on the differential effects of corticosteroids on fetal vascular systems.

## Key findings

- Corticosteroids significantly decreased umbilical artery pulsatility index.
- No significant changes were observed in the middle cerebral artery pulsatility index.
- Effects were consistent regardless of gestational age or pre-eclampsia status.

## Abstract

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).

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.

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.

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