Induction of labour for postdates in nulliparous women with uncomplicated pregnancy - is the caesarean section rate really lower?

Induction for "post-dates" is a very common procedure and in Queensland, Australia, accounts for 35.5% of all inductions. Systematic reviews all conclude that induction of labour does not increase the risk of caesarean section (CS). However, these reviews have generally included a mixed population and have not stratified for parity. We report in a retrospective cohort study involving only nulliparous women with uncomplicated singleton pregnancy at 40° to 416 weeks that compared to spontaneous labour, incidence of CS was significantly higher in the induction group, 22.2% versus 12.1% (OR 2.06; 95% CI 1.93-2.20) at 40° to 416 weeks versus spontaneous labour at 40° to 416 weeks; and also higher at 21.0% versus 14.9% (OR 1.52; 95% CI 1.34-1.73) at 40° to 406 weeks versus spontaneous labour at 41° to 416 weeks (expectant management).