Elective caesarean section at 38 weeks versus 39 weeks: neonatal and maternal outcomes in a randomised controlled trial

Objectives: To investigate whether elective caesarean section before 39 completed weeks of gestation increases the risk of adverse neonatal or maternal outcomes.

Design: Randomised controlled multicentre open-label trial.

Setting: Seven Danish tertiary hospitals from March 2009 to June 2011.

Population: Women with uncomplicated pregnancies, a single fetus, and a date of delivery estimated by ultrasound scheduled for delivery by elective caesarean section.

Methods: Perinatal outcomes after elective caesarean section scheduled at a gestational age of 38 weeks and 3 days versus 39 weeks and 3 days (in both groups ±2 days).

Main outcome measures: The primary outcome was neonatal intensive care unit (NICU) admission within 48 hours of birth. Secondary outcomes were neonatal depression, NICU admission within 7 days, NICU length of stay, neonatal treatment, and maternal surgical or postpartum adverse events.

Results: Among women scheduled for elective caesarean section at 38⁺³ weeks 88/635 neonates (13.9%) were admitted to the NICU, whereas in the 39⁺³ weeks group 76/637 neonates (11.9%) were admitted (relative risk [RR] 0.86, 95% confidence interval [95% CI] 0.65-1.15). Neonatal treatment with continuous oxygen for more than 1 day (RR 0.31; 95% CI 0.10-0.94) and maternal bleeding of more than 500 ml (RR 0.79; 95% CI 0.63-0.99) were less frequent in the 39 weeks group, but these findings were insignificant after adjustment for multiple comparisons. The risk of adverse neonatal or maternal outcomes, or a maternal composite outcome (RR 1.1; 95% CI 0.79-1.53) was similar in the two intervention groups.

Conclusions: This study found no significant reduction in neonatal admission rate after ECS scheduled at 39 weeks compared with 38 weeks of gestation.