Labor patterns in women with previous cesareans.

Little information exists to help determine the presence or significance of labor abnormalities in women attempting vaginal birth after previous cesarean. A case-control study was performed to obtain information on patterns of labor progress and the incidence of dysfunctional labor in patients having a trial of labor after previous cesarean delivery. Sixty-eight such women were matched to nulliparous and multiparous controls. Labor-curve characteristics for the group of women with previous cesarean differed significantly from those of both the nulliparas and multiparas. When stratified by history of previous vaginal birth, however, those with no previous vaginal birth were indistinguishable from nulliparous controls and those with a previous vaginal birth were indistinguishable from multiparous controls. Parity-specific criteria for the diagnosis of dysfunctional labor were thus indicated. Labor disorders were present most frequently in the previous-cesarean group with no previous vaginal birth (41.9%). This incidence did not differ significantly from that in the control nulliparas (27.1%) (P = .15), but did differ from that in the multiparas (15.8%) (P less than .01). Previous-cesarean patients with a previous vaginal birth had a frequency of labor disorders (14.3%) not significantly different from that of multiparous controls. We conclude that trial of labor in women with a previous cesarean should be evaluated by standard criteria for nulliparas if there has been no previous vaginal birth, and by criteria for multiparous women if there has been any previous infant born vaginally.