Trial of labor after cesarean delivery as an independent risk factor for intrapartum asphyxia in singleton deliveries beyond 37 weeks' gestation.

The aim of this study was to determine the factors associated with intrapartum asphyxia in singleton deliveries beyond 37 weeks' gestation. We reviewed the obstetric records of Japanese singleton deliveries after 37 weeks' gestation managed at Japanese Red Cross Katsushika Maternity Hospital from 2005 through 2010. Forty-nine cases were diagnosed as intrapartum asphyxia on the basis of an Apgar score <4 at 5 minutes or umbilical arterial pH <7.0 or both. Cases with umbilical arterial pH ≥7.1 and 1-minute Apgar score ≥7 were examined as controls (n=10,484). Logistic multivariate regression analysis showed that intrapartum asphyxia was independently associated with cases of trial of labor after cesarean delivery (adjusted odds ratio, 3.24; 95% confidence intervals, 1.0-11; p=0.04). Our findings may be encouraging for the counseling of patients regarding a possible attempt at trial of labor after cesarean delivery.