Effects of induction of labour versus expectant management in women with impending post-term pregnancies: the 41 week – 42 week dilemma

Post-term pregnancy, a pregnancy exceeding 294 days or 42 completed weeks, is associated with increased perinatal morbidity and mortality and is considered a high-risk condition which requires specialist surveillance and induction of labour. However, there is uncertainty on the policy concerning the timing of induction for post-term pregnancy or impending post-term pregnancy, leading to practice variation between caregivers. Previous studies on induction at or beyond 41 weeks versus expectant management showed different results on perinatal outcome though conclusions in meta-analyses show a preference for induction at 41 weeks. However, interpretation of the results is hampered by the limited sample size of most trials and the heterogeneity in design. Most control groups had a policy of awaiting spontaneous onset of labour that went far beyond 42 weeks, which does not reflect usual care in The Netherlands where induction of labour at 42 weeks is the regular policy. Thus leaving the question unanswered if induction at 41 weeks results in better perinatal outcomes than expectant management until 42 weeks.

In this study we compare a policy of labour induction at 41 + 0/+1 weeks with a policy of expectant management until 42 weeks in obstetrical low risk women without contra-indications for expectant management until 42 weeks and a singleton pregnancy in cephalic position. We will perform a multicenter randomised controlled clinical trial. Our primary outcome will be a composite outcome of perinatal mortality and neonatal morbidity. Secondary outcomes will be maternal outcomes as mode of delivery (operative vaginal delivery and Caesarean section), need for analgesia and postpartum haemorrhage (≥1000 ml). Maternal preferences, satisfaction, wellbeing, pain and anxiety will be assessed alongside the trial.

This study will provide evidence for the management of pregnant women reaching a gestational age of 41 weeks.

Dutch Trial Register (Nederlands Trial Register): NTR3431. Registered: 14 May 2012.