To Örebro University

Objective: To evaluate if induction of labour at 41 weeks improves perinatal and maternal outcomes in women with low risk pregnancies compared with expectant management and induction at 42 weeks.

Methods: A multicenter, randomised controlled superiority trial.

Women with low risk singleton pregnanies (n = 2760) were randomised to either induction or expectant management group. The primary outcome was a composite perinatal outcome including one or more of stillbirth, neonatal mortality, Apgar score < 7 at five minutes, pH < 7.00 or metabolic acidosis (pH < 7.05 and base deficit >12 mmol/L) in the umbilical artery, hypoxic ischaemic encephalopathy, intracranial haemorrhage, convulsions, meconium aspiration syndrome, mechanical ventilation within 72 hours, obstetric brachial plexus injury. Primary analysis was by intention to treat.

Results: The study was stopped early owing to a significantly higher rate of perinatal mortality in the expectant management group (no deaths compared to six deaths, p = 0.03). The primary outcome did not differ: 2.4 % (33/1381) in the induction group and 2.2 % (31/1379) in the expectant management group (RR 1.06, 95 %CI 0.65 to 1.73; p = 0.90). The proportion of caesarean delivery, instrumental vaginal delivery, or any major maternal morbidity did not differ between the groups.

Conclusions: There was no significant difference in the primary composite outcome when comparing induction at 41 weeks with expectant management and induction at 42. However, a reduction of the secondary outcome perinatal mortality was observed without increasing adverse maternal outcomes. To offer induction at 41 weeks could be one of few interventions that reduces the rate of stillbirths.