Randomised comparison of early versus late induction of labour in post-term pregnancy.

In a prospective randomised study of mothers referred for prolonged pregnancy (around the 42nd week) 214 (group 1) were submitted to attempted induction of labour and 195 (group 2) assigned to continue for a further week without intervention. Strict selection criteria were used for the certainty of term. Mothers in group 2 were given regular non-stress tests to ensure fetal wellbeing, as were those in group 1 in whom induction failed. In group 1, 48 (23%) out of 210 first attempted inductions failed. In group 2, 135 (69%) of the births started spontaneously as compared with 38 (18%) in group 1. The mean duration of labour was 7.5 hours in each group. There was no significant difference in incidence of operative delivery, use of analgesics, or signs of perinatal asphyxia. Significantly more children in group 1 needed phototherapy for hyperbilirubinaemia. There was a clustering of births in the late afternoon and evening, which was most pronounced in group 1. A policy of vigilant non-intervention up to the 44th completed week of pregnancy does not appear to jeopardize mother or fetus.