Photo Credit: Elena Pimukova

The following is a summary of “Optimal timing of antenatal COrticosteroid administration in pregnancies complicated by early-onset fetal growth restriction: results of a large multicenter cohort study (the OPTICORE study),” published in the December 2024 issue of Obstetrics and Gynecology by Meent et al.

Early-onset fetal growth restriction (FGR), often a result of placental insufficiency, frequently necessitates iatrogenic preterm birth. The administration of antenatal corticosteroids is well-established in mitigating neonatal morbidity and mortality associated with preterm birth, with maximum benefit observed when delivery occurs within two weeks of treatment. However, international guidelines lack specificity regarding the optimal timing of corticosteroid administration in FGR pregnancies, leading to practice variability. 

This study aimed to compare the two predominant timing strategies for antenatal corticosteroid administration in the Netherlands for early-onset FGR: Strategy A, administered when the umbilical artery pulsatility index (PI) exceeds the 95th percentile with positive end-diastolic flow, and Strategy B, administered when the umbilical artery shows absent or reversed end-diastolic velocity.

A multicenter retrospective cohort study was conducted across six tertiary hospitals in the Netherlands from 2012 to 2021, with three hospitals following each timing strategy. The primary outcome was a composite of perinatal and in-hospital mortality, while secondary outcomes aligned with the core outcome set for FGR. Mixed effects analyses, adjusted for birthweight z-score and gestational age at birth, were employed to compare the strategies.

The study included 1,453 patients, with 871 and 582 treated under Strategies A and B, respectively. The mean gestational ages at corticosteroid administration were 28 weeks and 3 days for Strategy A and 28 weeks and 4 days for Strategy B, with comparable birthweights between the groups. Although not statistically significant, Strategy B was associated with higher perinatal and in-hospital mortality (7.2% vs. 9.8%; adjusted OR 1.47; 95% CI 0.97–2.22). 

Both strategies had similar percentages of deliveries within the corticosteroid therapeutic window (52.8% for Strategy A and 53.6% for Strategy B), with a median interval of six days between corticosteroid administration and delivery in both groups. Strategy B exhibited higher rates of necrotizing enterocolitis (3.7% vs. 7.6%; adjusted OR 2.18; 95% CI 1.29–3.69) but lower rates of respiratory distress syndrome (39.6% vs. 34.5%; adjusted OR 0.63; 95% CI 0.45–0.88) and bronchopulmonary dysplasia (18.9% vs. 17.4%; adjusted OR 0.69; 95% CI 0.50–0.96). Other outcomes showed no significant differences between the strategies.

In conclusion, Strategy B was linked to higher rates of perinatal and in-hospital mortality, not attributable to differences in corticosteroid administration timing relative to delivery. The findings underscore the need for improved timing protocols for antenatal corticosteroids in early-onset FGR and further exploration of other ante- and postnatal management factors influencing neonatal outcomes.

Source: sciencedirect.com/science/article/pii/S0002937824011955