Objective: To determine the risks and benefits of an elective Caesarean section (CS) at term in healthy nulliparous women.
Methods: We conducted a population-based cohort study of deliveries between 1994 and 2002. Using bivariate and multivariable techniques, we compared maternal and neonatal outcomes in healthy nulliparous women who had undergone elective pre-labour CS (using breech presentation as a surrogate) with those in women who had undergone spontaneous labour with anticipated vaginal delivery (SL) at full term.
Results: There were 1046 deliveries in the pre-labour CS group and 38 021 in the SL group. Life-threatening maternal morbidity was similar in each group. Life-threatening neonatal morbidity was decreased in the CS group (RR 0.34; 99% CI 0.12 to 0.97). Subgroup analysis of the SL group by mode of delivery demonstrated the increased neonatal risk was associated with operative vaginal delivery and intrapartum CS but not spontaneous vaginal delivery.
Conclusion: An elective pre-labour Caesarean section in a nulliparous woman at full term decreased the risk of life-threatening neonatal morbidity compared with spontaneous labour with anticipated vaginal delivery. However, the 63% of women with spontaneous labour who achieved a spontaneous vaginal delivery would not have benefited from delivery by Caesarean section. Further research is needed to better identify women with an increased likelihood of an operative vaginal or intrapartum Caesarean section, as this may assist maternity caregivers in decision-making about childbirth. Further research is also needed to determine if these findings can be confirmed in a prospective study.