Caesarean section improves neonatal outcomes only from 24 + 0 weeks for periviable breech but not for cephalic infants.

Background: Although caesarean delivery at periviable gestations may minimize birth trauma, it may not necessarily improve perinatal outcomes. The aim of this study was to assess the impact of mode of birth on outcomes for breech versus cephalic presentation at 22 + 0-25 + 6 weeks.Methods: Retrospective cohort study of single, nonanomalous infants at 22 + 0-25 + 6 weeks gestation born at a tertiary center in Australia. Neonatal outcomes were analyzed comparing both breech and cephalic presentation and mode of delivery.Results: Six hundred and eighty eight women fulfilled the inclusion criteria with 39.7% (273/688) breech and 60.3% (415/688) cephalic infants. Survival was 31.5% (86/273) and 38.1% (158/415) in the breech and cephalic cohorts respectively. Vaginal breech infants had reduced odds of survival compared to the vaginal cephalic group (aOR 0.37, 95% CI 0.17-0.75, p < .01) with no difference in survival if delivery occurred by caesarean section. Vaginal breech birth had higher odds of very low Apgar scores, stillbirth, and neonatal death. At 22 + 0-22 + 6 weeks, outcomes were universally fatal. At 24 + 0-24 + 6 and 25 + 0-25 + 6 weeks, vaginal breech birth had lower odds of survival (aOR 0.33, 95% CI 0.13-0.84, p < .05 and aOR 0.10, 95% CI 0.03-0.34, p < .001 respectively) compared to caesarean breech births.Conclusions: Caesarean section improves perinatal outcomes for periviable breech infants > 24 + 0 weeks.