Umbilical Artery Doppler Improvement After Steroid Administration Is Associated With Improved Fetal Growth

Betamethasone (BMZ) is commonly given for fetal growth restriction (FGR) with abnormal umbilical artery Doppler (UAD) velocimetry. Improvement of UAD can be seen after BMZ, but the impact of such improvement on fetal growth remains unclear. We tested the hypothesis that UAD improvement after BMZ is associated with improved growth and decreased risk for small for gestational age (SGA) infants. This was a retrospective cohort study of pregnancies complicated by FGR with abnormal UAD between 24-34 weeks gestational age. Abnormal UAD included elevated (pulsatility index >95%ile), absent end diastolic flow (EDF), or reversed EDF. We included patients who received BMZ at provider discretion within 1 week of abnormal UAD and had a growth assessment performed before and after BMZ administration. Improvement was defined as any improvement in category of UAD within 2 weeks of BMZ. The primary outcome was SGA. Secondary outcomes included growth velocity, GA at delivery, latency from BMZ administration to delivery, and neonatal morbidity. These outcomes were compared between patients with and without UAD improvement. Multivariable logistic regression was used to adjust for confounders. Of the 49 pregnancies meeting inclusion criteria, UAD improved in 28 (57.1%) after BMZ. Patients with improved UAD were significantly less likely to deliver an SGA infant compared to those without UAD improvement (aOR 0.21, 95% CI 0.05-0.93). Improved UAD was associated with higher growth velocity over the remainder of the pregnancy. Patients with UAD improvement had longer latency and delivered at a later gestational age than those without improvement. Composite neonatal morbidity was similar between groups after controlling for severity of UAD at diagnosis and GA at delivery. UAD improved in more than half of growth restricted fetuses following BMZ. UAD improvement was associated with a reduced risk of SGA, improved growth velocity, longer latency and later gestational age at delivery. UAD response to BMZ may be useful to further risk stratify FGR.View Large Image Figure ViewerDownload Hi-res image Download (PPT)