Prolonged Labor & Potential Risk Factors

For the 5-year period of 1990-1994, 9018 nulliparas delivering at the National Maternity Hospital in Dublin met inclusion criteria for the study. Of these, 147 (1.6%) had prolonged labor> 12 hours, a singleton gestation, cephalic presentation, and labor occurring at>37 weeks' gestation. Each of the 147 patients were matched with the next nulliparous patient who delivered with labor <12 hours and fulfilled the inclusion criteria. Prolonged labor was due to insufficient uterine action in 65%, persistent occipitoposterior position in 24%, and cephalopelvic disproportion in 11% of cases. Multivariate analysis showed cervical dilatation <2 cm on admission, early epidural placement, epidural placement at ≥2 cm, and birth weight>4000 g to be significant independent predictors (odds ratios 3.1, 42.7, 5.1, and 10.2, respectively). Maternal weight and body mass index already have been implicated in the etiology of abnormal labor, with an increased requirement for oxytocin augmentation and increased primary cesarean delivery rate noted in obese patients. These factors, as stated by the authors, cannot be influenced once the patient has been admitted in labor.