Predictors of vaginal delivery in nulliparous mothers

BACKGROUND: Nulliparity is an obstetric high-risk group whose labor, compared with multiparae, are more likely to develop labor abnormalities that requires intervention. The aim of this report is todetermine factors that influence vaginal delivery in nulliparae. MATERIALS AND METHODS: A prospective cross-sectional study was done on 286 eligible booked nulliparae in labor, to determine factors associated with vaginal delivery. Information about each patient's social demographic factors, and physical characteristics such as height and weight, events in labor and mode of delivery were recorded in the data sheet. Bivariate analysis was done using Chi square, while multivariate analysis was done using logistic regression. Level of significance was put at P < 0.05. RESULTS: Of a total of 944 primigravidae delivered in the unit during the study period, 286 (30.3%) were eligible for the study. Vaginal delivery was achieved in 214 (74.8%) of the eligible parturient, while 72 (25.2%) had emergency caesarean delivery. Indications for the caesarean delivery were: failure to progress (46; 63.9%), fetal distress (20; 27.8%), maternal distress (5; 8.0%), and rapidly developing pre-eclampsia in labor (1, 0.3%). The birth weight of the baby ranged between 2.0 and 4.5 kg with mean weight of 3.1 ± 0.4 kg. Birth weight (odd ratio OR = 0.40, 95% confidence interval CI = 0.21-0.78), fetal head engagement in early labor (OR = 10.30, 95% CI = 1.35-78.69), and maternal body mass index (BMI) (odd ratio OR = 2.08, 95% confidence interval CI = 1.03-4.20) were found to be predictors of vaginal delivery. CONCLUSION: Normal range of maternal BMI, fetal head engagement and normal range of fetal birth weight were found to be the factors associated with vaginal delivery in nulliparae. Variations in these three factors may be the underlying reason for failure to progress, which is the most common indication for caesarean section among this population of parturient.