Effect of delivery mode on neonatal outcome among preterm infants: an observational study.

BACKGROUND: The optimal mode of delivery as a predictor for outcomes in preterm infants is under debate. The purpose of this study was to evaluate the effect of the delivery mode on neonatal outcome among preterm infants in different birthweight categories. METHODS: A retrospective analysis of singleton preterm deliveries from 23 + 0 to 33 + 6 gestational weeks was performed. Infants were categorized based on birthweight as large for gestational age (LGA), appropriate for gestational age (AGA) and small for gestational age (SGA). The Apgar score at 5 min served as the main outcome parameter. A sensitivity analysis was performed to adjust for maternal age, parity and fetal malformations as potential confounders. RESULTS: Out of 1320 singleton preterm infants, 970 (73.5%) were delivered by cesarean section and 350 (26.5%) were delivered vaginally. The AGA infants between 23 + 0 and 27 + 6 weeks showed better outcomes after cesarean section (p < 0.01 from 23 + 0-24 + 6; p = 0.03 from 25 + 0-27 + 6), whereas AGA infants between 31 + 0 and 33 + 6 gestational weeks showed better outcomes after vaginal delivery (p = 0.02). Cesarean section was beneficial in extremely and very preterm SGA infants (p = 0.01 from 25 + 0-27 + 6; p = 0.02 from 28 + 0-30 + 6). The sensitivity analysis showed no confounding effect of other variables. CONCLUSION: There is a benefit from cesarean section in AGA preterm infants until 28 weeks of gestation and in SGA preterm infants until 31 weeks of gestation. Vaginal delivery should be chosen for moderately preterm AGA infants.