Caesarean section rates and adverse neonatal outcomes after induction of labour versus expectant management in women with an unripe cervix: a secondary analysis of the HYPITAT and DIGITAT trials

Objective To evaluate caesarean section and adverse neonatal outcome rates after induction of labour or expectant management in women with an unripe cervix at or near term. Design Secondary analysis of data from two randomised clinical trials. Setting Data were collected in two nationwide Dutch trials. Population Women with hypertensive disease (HYPITAT trial) or suspected fetal growth restriction (DIGITAT trial) and a Bishop score <= 6. Methods Comparison of outcomes after induction of labour and expectant management. Main outcome measures Rates of caesarean section and adverse neonatal outcome, defined as 5-minute Apgar score <= 6 and/or arterial umbilical cord pH <7.05 and/or neonatal intensive care unit admission and/or seizures and/or perinatal death. Results Of 1172 included women with an unripe cervix, 572 had induction of labour and 600 had expectant management. We found no significant difference in the overall caesarean rate (difference -1.1%, 95% CI -5.4 to 3.2). Induction of labour did not increase caesarean rates in women with Bishop scores from 3 to 6 (difference -2.7%, 95% CI -7.6 to 2.2) or adverse neonatal outcome rates (difference -1.5%, 95% CI -4.3 to 1.3). However, there was a significant difference in the rates of arterial umbilical cord pH <7.05 favouring induction (difference -3.2%, 95% CI -5.6 to -0.9). The number needed to treat to prevent one case of umbilical arterial pH <7.05 was 32. Conclusions We found no evidence that induction of labour increases the caesarean rate or compromises neonatal outcome as compared with expectant management. Concerns over increased risk of failed induction in women with a Bishop score from 3 to 6 seem unwarranted.