(1240) Maternal body mass index and neonatal respiratory outcomes following antenatal corticosteroid administration

Objective:
Prior studies demonstrate improved preterm neonatal outcomes with administration of antenatal corticosteroids (ACS). However, no studies have investigated the interaction of this fixed dose medication with maternal weight or body mass index. Our study assessed the association of maternal weight and body mass index with neonatal outcomes after ACS administration. We hypothesized that steroids would have reduced efficacy at improving neonatal respiratory outcomes in cases of maternal obesity.

Study Design:
This was a retrospective cohort study of all patients delivering at a single academic institution in New York City from January 1, 2013 - December 31, 2023. Patients were included if they received two doses of betamethasone prior to delivery and had available maternal weight and height data. Patients were excluded if they received > 2 doses, did not deliver at our institution, received ACS at > 37 weeks, or experienced a stillbirth. We assessed electronic medical records for clinical and demographic data. Our primary outcome was a neonatal respiratory composite (transient tachypnea of the newborn, respiratory distress syndrome, use of CPAP for > 12 hours, oxygen for > 24 hours, intubation, or surfactant). Multivariable logistic regression models controlling for potential confounders examined association of maternal body mass index and weight with neonatal outcomes.

Results:
2,638 patients met inclusion criteria. Of these, 850 had obesity (Table 1). Patients with obesity were more likely to have diabetes, hypertension, chorioamnionitis, large for gestational age fetuses, and deliver at earlier gestational ages (Table 1). After controlling for potential confounders, neonates of patients with obesity had significantly decreased rates of intubation. We found no other differences in neonatal outcomes by maternal weight or BMI (Table 2).

Conclusion:
Although obese patients receiving ACS were less likely to experience neonatal intubation, other neonatal respiratory outcomes following ACS administration did not differ significantly by maternal weight or BMI.