The purpose of this study was to determine the continuing effectiveness of active management of labor, a protocol that involves early detection and correction of dystocia with oxytocin in spontaneous cephalic nulliparous labor, by analysis of the contribution of this cohort to a doubled overall nulliparous cesarean delivery rate.

This was a retrospective analysis of annually collated institutional data on cesarean delivery and perinatal outcome.

From 1989 to 2000, 81,855 women were delivered at the National Maternity Hospital, of whom 34,201 women (42%) were nulliparous; the annual proportion of nulliparous women in spontaneous labor decreased progressively from 83% to 60%; the overall nulliparous cesarean rate increased from 8.1% to 16.6%. Cesarean birth rate among nulliparous women in spontaneous labor, although showing a significant upward trend between 1989 and 2000 (2.4%-4.8%; P=.001), was stable, averaging 5% for the last 8 years (P=.705); the peripartum death rate in this group fell significantly (P=.024). Comparing results for 1989 with results for 2000, nulliparous women in spontaneous labor accounted for 14% of the overall increase in cesarean deliveries (dystocia, 5%), compared with 51% for nulliparous women with induced labor. The perinatal mortality rate in term infants was unchanged.

Active management of spontaneous first labors remains an effective protocol for the promotion of vaginal delivery with low peripartum mortality rates; factors other than dystocia in spontaneous labor account for the progressive increase in the nulliparous cesarean delivery rate.