Practice variation in timing of antenatal corticosteroid administration in early-onset fetal growth restriction: A secondary analysis of the Dutch STRIDER study

Introduction: In early-onset fetal growth restriction the fetus fails to thrive in utero due to unmet fetal metabolic demands. This condition is linked to perinatal mortality and severe neonatal morbidity. Maternal administration of corticosteroids in high-risk pregnancies for preterm birth at a gestational age between 24 and 34 weeks has been shown to reduce perinatal mortality and morbidity. Practice variation exists in the timing of the administration of corticosteroids based on umbilical artery monitoring findings in early-onset fetal growth restriction. The aim of this study was to examine differences in neonatal outcomes when comparing different corticosteroid timing strategies. Material and methods: This was a post-hoc analysis of the Dutch STRIDER trial. We examined neonatal outcomes when comparing institutional strategies of early (umbilical artery pulsatility index >95th centile) and late (umbilical artery shows absent or reversed end-diastolic flow) administration of corticosteroids. The primary outcomes were neonatal mortality and a composite of neonatal mortality and neonatal morbidity, defined as bronchopulmonary dysplasia, intraventricular hemorrhage, necrotizing enterocolitis or retinopathy of prematurity. We also analyzed predictors for adverse neonatal outcomes, including gestational age at delivery, birthweight, maternal hypertensive disorders, and time interval between corticosteroids and birth. Results: A total of 120 patients matched our inclusion criteria. In 69 (57.5%) the early strategy was applied and in 51 (42.5%) patients the late strategy. Median gestational age at delivery was 28 4/7 (± 3, 3/7) weeks. Median birthweight was 708 (± 304) g. Composite primary outcome was found in 57 (47.5%) neonates. No significant differences were observed in the primary outcome between the two strategies (neonatal mortality adjusted odds ratio [OR] 1.22, 95% CI 0.44–3.38; composite primary outcome adjusted OR 1.05, 95% CI 0.42–2.64). Only gestational age at delivery was a significant predictor for improved neonatal outcome (adjusted OR 0.91, 95% CI 0.86–0.96). Conclusions: No significant differences in neonatal outcomes were observed when comparing early and late strategy of antenatal corticosteroid administration on neonatal outcomes in pregnancies complicated by early-onset fetal growth restriction. We found no apparent risk contribution of interval between corticosteroid administration and delivery in multivariate analysis. Gestational age at delivery was found to be an important predictor of neonatal outcome.