"Early rupture of membranes" after the spontaneous onset of labor as a risk factor for cesarean delivery

Objective: The objective of this study was to examine if patients with "early rupture of membranes (ROM)" after spontaneous onset of labor are at increased risk of cesarean section. Study design: The rate of cesarean section was examined in 447 term singleton nulliparas who were admitted after the spontaneous onset of labor. The cases were divided into 2 groups: (1) "early ROM", defined as ROM at a cervical dilatation <4 cm (n = 109); and (2) "late ROM", ROM at a cervical dilatation ≥4 cm (n = 338). Results: (1) "Early ROM" occurred in 24.4% of the cases and the overall cesarean section rate was 5.6%; (2) there were no significant differences in the clinical characteristics including prepregnancy BMI, proportion of complicated pregnancies, total duration of labor, proportion of regional anesthesia, gestational age at delivery, and birthweight between the two groups of cases. However gravidas with "early ROM" were of advanced maternal age and had less cervical dilation on admission, shorter duration of 1st stage of labor, and more frequent use of oxytocin augmentation; (3) patients with "early ROM" had a threefold higher rate (11.9% vs. 3.6%) of cesarean section and a fourfold higher rate (11.9% vs. 3.0%) of cesarean section due to failure of progress than did those with "late ROM" (p < 0.005 for each); (3) 92% (23/25) of cesarean sections were performed due to failure to progress; and (4) there was no significant difference in the rate of histologic chorioamnionitis between the two groups of cases. Conclusion: "Early ROM" after the spontaneous onset of labor is a risk factor for cesarean section in term singleton nulliparas.