Optimal Timing of Delivery among Low-Risk Women with Prior Caesarean Section: A Secondary Analysis of the WHO Multicountry Survey on Maternal and Newborn Health

Objective To investigate optimal timing of elective repeat caesarean section among low-risk pregnant women with prior caesarean section in a multicountry sample from largely low-and middle-income countries. Design Secondary analysis of a cross-sectional study. Setting Twenty-nine countries from the World Health Organization Multicountry Survey on Maternal and Newborn Health. Population 29,647 women with prior caesarean section and no pregnancy complications in their current pregnancy who delivered a term singleton (live birth and stillbirth) at gestational age 37-41 weeks by pre-labour caesarean section, intra-partum caesarean section, or vaginal birth following spontaneous onset of labour. Methods We compared the rate of short-term adverse maternal and newborn outcomes following pre-labour caesarean section at a given gestational age, to those following ongoing pregnancies beyond that gestational age. Main Outcome Measures Severe maternal outcomes, neonatal morbidity, and intra-hospital early neonatal mortality. Results Odds of neonatal morbidity and intra-hospital early neonatal mortality were 0.48 (95% confidence interval [CI] 0.39-0.60) and 0.31 (95% CI 0.16-0.58) times lower for ongoing pregnancies compared to pre-labour caesarean section at 37 weeks. We did not find any significant change in the risk of severe maternal outcomes between pre-labour caesarean section at a given gestational age and ongoing pregnancies beyond that gestational age. Conclusions Elective repeat caesarean section at 37 weeks had higher risk of neonatal morbidity and mortality compared to ongoing pregnancy, however risks at later gestational ages did not differ between groups.