Risk factors and outcome of failure to progress during the first stage of labor: a population-based study.

BACKGROUND: One of the major indications for Cesarean section (CS) is failure of labor to progress. This study was aimed at defining obstetric risk factors for failure of labor to progress during the first stage, and to determine pregnancy outcome.

METHODS: A population-based study comparing all singleton, vertex, term deliveries between the years 1988 and 1999 with an unscarred uterus, complicated with failure of labor to progress during the first stage with deliveries without non-progressive labor (NPL). Multiple logistic regression analysis was performed to investigate independent obstetric risk factors associated with failure of labor to progress during the first stage.

RESULTS: Failure to progress during the first stage of labor complicated 1.3% (n = 1197) of all deliveries included in the study (n = 92 918), and resulted in CS. Independent risk factors for failure of labor to progress during the first stage, using a multivariable analysis, were premature rupture of membranes (PROM; OR = 3.8, 95% CI 3.2-4.5), nulliparity (OR = 3.8, 95% CI 3.3-4.3), labor induction (OR = 3.3, 95% CI 2.9-3.7), maternal age > 35 years (OR = 3.0, 95% CI 2.6-3.6), birth weight > 4 kg (OR = 2.2, 95% CI 1.8-2.7), hypertensive disorders (OR = 2.1, 95% CI 1.8-2.6), hydramnios (OR = 1.9, 95% CI 1.5-2.3), fertility treatment (OR = 1.8, 95% CI 1.4-2.4), epidural analgesia (OR = 1.6, 95% CI 1.4-1.8) and gestational diabetes (OR = 1.4, 95% CI 1.1-1.7). Although newborns delivered after failure of labor to progress during the first stage had significantly higher rates of Apgar scores lower than 7 at 1 and 5 min as compared with the controls (18.2% vs. 2.1%; P < 0.001 and 1.3% vs. 0.2%; P < 0.001, respectively), no significant differences were noted between the groups regarding perinatal mortality (0.3% vs. 0.4%; P = O.329). Maternal anemia and accordingly packed cells transfusion (47.4% vs. 22.8%; P < 0.001 and 5.6% vs. 1.0%; P < 0.001, respectively) were higher among pregnancies complicated with failure of labor to progress during the first stage as compared with the controls.

CONCLUSIONS: Major risk factors for failure of labor to progress during the first stage were PROM, nulliparity, induction of labor and older maternal age. Indications for labor induction should be carefully evaluated in order to decrease the rate of operative deliveries.