Objective: to determine whether delivery by caesarean section (CS) and receipt of antenatal steroids (ANS) in vertex-presenting singletons with a gestational age (GA) between 24 and 30 weeks is associated with improved overall survival and severe intraventricular haemorrhage (sIVH)-free survival.
Design: retrospective cohort study.
Setting: twenty-five neonatal intensive care units in Argentina, Brazil, Chile, Paraguay, Peru and Uruguay (shared database of the Neocosur Network).
Study sample: 4386 vertex-presenting singleton newborns 24 to 30 weeks’ GA with birth weight between 500 and 1500 g and no major congenital malformations delivered in participating hospitals between 2001 and 2011. The authors did not report any losses to follow-up.
Assessment of prognostic factor: administration of ANS (at least one dose) and/or CS. Newborns were classified into four groups based on the mode of delivery and whether they had received ANS or not.
Outcome assessment: the outcome variables “survival” and “sIVH-free survival” (severe, grades III-IV) at discharge were compared in the four groups, with the group of newborns delivered by CS and that received ANS set as the reference category. Logistic regression multivariate analysis was performed to estimate unadjusted and adjusted odd ratios (ORs) The authors analysed three regression models (Model 1 [M1]: unadjusted analysis of outcome variables in all four groups; Model 2 [M2]: adjusted analysis adding the covariates sex, Apgar < 3 at 1 and 5 minutes, sepsis < 72 h, premature rupture of membranes [PROM] > 18 h and small for gestational age [SGA] for the 24-25 weeks’ GA subgroup; Model 3 [M3]: analysis including the same covariates for the 26-30 weeks’ GA subgroup).
Main results: 45.8% were born by vaginal delivery (VD). Of the total NBs, 77.3% had received ANS (84.5% of those born by CS and 68.9% of those born by VD). There were statistically significant differences between the VD and the CS groups in perinatal and demographic variables (except in sex). The unadjusted comparison by mode of delivery showed increased survival and sIVH-free survival in NBs delivered by CS.
M1 showed increased survival in NBs that received ANS, independent of the mode of delivery. M2 suggested an association between the combination of ANS/CS with improved survival and sIVH-free survival compared to the use of ANS in NBs with VD (OR, 0.62 [95% confidence interval (95 CI), 0.41 to 0.92] and OR, 0.56 [95 IC, 0.37 to 0.85], respectively). M3 only showed a reduced survival in NBs delivered vaginally that did not receive ANS (OR, 0.35; 95 CI, 0.28 to 0.46) and increased sIVH in NBs that did not receive ANS, especially in those born by VD (OR, 0.36; 95 CI, 0.28 to 0.46).
Conclusion: the use of ANS was associated with an increased survival and sIVH-free survival, independent of mode of delivery, except in infants born at 24 to 25 weeks’ gestation, in whom the combination of ANS/CS was associated with improvements compared to VD.
Conflicts of interest: none.
Funding source: voluntary and not-for-profit professional network.