Introduction
The appropriate time for termination of pregnancy has always been a concern of medical staff. Foetal lung maturity gradually increases with gestational age, and premature termination of pregnancy may lead to neonatal respiratory disease syndrome (RDS), whereas late termination may increase maternal and neonatal risks. Neonates delivered at 36 to 38 weeks after confirmed foetal lung maturity are at higher risk of adverse outcomes than those delivered at 39 to 40 weeks1. Pulmonary maturity generally occurs after full-term birth (39 0/7-40 6/7 weeks)2. Therefore, inducing pregnancy at 39 0/7-40 6/7 weeks may be proper from the angle of foetal lung maturity.
At present, elective labour induction is commonly performed after 41 weeks in low-risk women without labour onset3,4. However, with increases in gestational weeks, increases are observed in foetal weight, the probability of macrosomia, the rate of cephalopelvic disproportion, and the occurrence of shoulder dystocia, caesarean section, neonatal asphyxia and birth injury5-8. Thus, we sought to determine whether inducing low-risk pregnant women in advance at 40 weeks will lead to improved maternal and foetal outcomes. Therefore, the goal of this study was to compare maternal and foetal outcomes between termination gestational age at 40 0/7-40 6/7 and 41 0/7-41 6/7 weeks.