Outcomes of elective labour induction and elective caesarean section in low-risk pregnancies between 37 and 41 weeks' gestation.

Objective: To compare maternal and neonatal outcomes after elective induction of labour and elective Caesarean section with outcomes after spontaneous labour in women with low-risk, full-term pregnancies.

Methods: We extracted birth data from 1996 to 2005 from an obstetrical database. Singleton pregnancies with vertex presentation, anatomically normal, appropriately grown fetuses, and no medical or surgical complications were included. Outcomes after elective induction of labour and elective Caesarean section were compared with the outcomes after spontaneous labour, using chi-square and Student t tests and logistic regression.

Results: A total of 9686 women met the study criteria(3475 nulliparous, 6211 multiparous). The incidence of unplanned Caesarean section was higher in nulliparous women undergoing elective induction than in those with spontaneous labour (P < 0.001). Postpartum complications were more common in nulliparous and multiparous women undergoing elective induction (P < 0.001 and P < 0.01, respectively) and multiparous women undergoing elective Caesarean section, (P < 0.001). Rates of triage in NICU were higher in nulliparous women undergoing elective Caesarean section (P < 0.01), and requirements for neonatal free-flow oxygen administration were higher in nulliparous and multiparous women undergoing elective Caesarean section (P < 0.01 for each). Unplanned Caesarean section was 2.7 times more likely in nulliparous women undergoing elective induction of labour (95% CI 1.74 to 4.28, P < 0.001) and was more common among nulliparous and multiparous women undergoing induction of labour and requiring cervical ripening (P < 0. 001 and P < 0.05, respectively).

Conclusion: Elective induction leads to more unplanned Caesarean sections in nulliparous women and to increased postpartum complications for both nulliparous and multiparous women. Elective Caesarean section has increased maternal and neonatal risks.