Labor after previous cesarean: influence of prior indication and parity

To determine whether the risk of cesarean for women who had trials of labor after one prior cesarean differs from that of nulliparas overall and by indications for those cesareans.

We reviewed medical records of women who had trials of labor after cesareans between July 1984 and June 1996, and of nulliparas who delivered between December 1994 and August 1995. Cesarean rates for women with prior cesareans were compared with the rates for nulliparas overall and by prior cesarean indication (breech, failure to progress, nonreassuring fetal testing, or other). Lengths of labor for women who had repeat cesareans for failure to progress in index pregnancies were compared by prior cesarean indication.

The cesarean rate was 28.7% (634 of 2207) for the prior cesarean group and 13.5% (219 of 1617) for nulliparas (P =.001), and varied according to the prior cesarean indication (13.9%, 37.3%, 25. 4%, and 24.8% for breech, failure to progress, nonreassuring fetal testing, and other, respectively). Mean durations of labor in the index pregnancies for women who had cesareans for failure to progress were 13.9, 11.5, 13.4, and 15.1 hours for breech, failure to progress, nonreassuring fetal testing, and other, respectively.

Overall rates of cesareans were higher for women with one prior cesarean than for nulliparas. Rates of cesareans after trials of labor were related to the prior cesarean indications. Rates were highest for women whose prior cesareans were for failure to progress and lowest for women whose prior cesareans were for breech. The latter group had a rate that was essentially identical to that of nulliparas. Among women with cesareans for failure to progress in index pregnancies, lengths of labor were shorter for those whose prior cesareans were for failure to progress than for those whose prior cesareans were for other indications, suggesting that physicians may intervene earlier in these cases.