145: Clinical implications of changes in umbilical artery Dopplers after betamethasone

Umbilical artery Dopplers (UAD) are used for surveillance of fetal growth restriction (FGR). Improvement in UAD is observed in some patients after betamethasone (BMZ), but the clinical impact of a change or lack thereof is unclear. We investigated changes in UAD after BMZ and the association with delivery/neonatal outcomes. This was a retrospective cohort study of singleton FGR pregnancies from 240-336 weeks with abnormal UAD at a single institution from 2014-2015. Abnormal UAD were: elevated (UA pulsatility index >95th %ile), absent end diastolic flow (AEDF), or reversed end diastolic flow (REDF). Improvement was defined as any improvement in category of UAD within 2 weeks of BMZ. Sustained improvement was defined as improvement lasting until delivery, whereas unsustained were those only transiently improved. The primary outcome was latency defined as interval from diagnosis to delivery. Secondary outcomes were other delivery outcomes and a composite of neonatal outcomes including intubation, necrotizing enterocolitis, ionotropic support, and intraventricular hemorrhage. Time-to-event analysis was used to estimate and compare latency between groups. Of the 162 FGR pregnancies with abnormal UAD, 72 received BMZ and repeat ultrasounds. UAD improved in 36 (50%, 95% CI 38%, 62%) patients who received BMZ, with 21 (29.1%) having sustained improvement. Patients with hypertension (25.0% vs 5.6%, P=0.02) and illicit drug use(19.4% vs 0.0%, P=0.01) were less likely to have improvement in UAD. Patients with improved UAD had significantly longer latency (median days [IQR]: 6 [3, 9] vs. 5 (3, 7]), P=0.04) (Figure) and delivered at a greater gestational age (35±2.5 vs 33±3.5, P=0.02) than those without improvement. The composite neonatal outcome and other delivery outcomes are also improved in patients with improvement in UAD, although the differences were not statistically significant (Table). Similar trends were noted even in patients with unsustained improvement. UAD improved in half of patients with FGR following BMZ. Improvement was associated with longer latency and greater gestational age at delivery, and a tendency towards lower neonatal morbidity. This suggests that UAD response to BMZ may be used to further risk stratify patients with FGR.View Large Image Figure ViewerDownload Hi-res image Download (PPT)