RESUMEN
OBJECTIVE: To compare the cesarean section (CS) rates of obstetricians with a preference of labor induction at early versus late gestational age. MATERIAL AND METHODS: Medical records of women who were low risk, nulliparous, singleton pregnancy, and >37 weeks and delivered their babies, were reviewed. Obstetricians, who preferred labor induction at<41 weeks, were allocated to the early induction group; and the other obstetricians were allocated to the late induction group. RESULTS: The late induction group had a higher percentage of labor induction at ≥41 weeks, compared with the early induction group (21% vs. 8%, p = 0.007). The late induction group had a lower CS rate (11.0% vs. 19.1%, p < 0.001). Multivariable Cox proportional hazard model revealed that the early induction group (hazard ratio [HR] = 2.14, p < 0.001), maternal age (HR = 1.04, p = 0.001), premature rupture of membranes (HR = 1.59, p = 0.006), and birth body weight (kg, HR = 2.13, p < 0.001) were independent predictors of CS. In women receiving labor induction (n = 312), birth body weight (kg, HR = 1.72, p = 0.04) was the sole predictor of CS; and there is a trend that the early induction group (HR = 1.54, p = 0.051) has a higher CS rate, compared with the late induction group. However, gestational age at labor induction was not a predictor of CS. CONCLUSION: In low-risk pregnancies, obstetricians preferring labor induction at early gestational age seem to be associated with a higher CS rate, compared with obstetricians preferring labor induction at late gestational age. Nonetheless, the above finding seems to be associated with physician's factor, instead of gestational age at labor induction.