Prediction of dystocia-related cesarean section risk in uncomplicated Taiwanese nulliparas at term.

PURPOSE: We aimed to assess risk factors for dystocia-related cesarean section (CS) in uncomplicated Taiwanese nulliparas at term

METHODS

We reviewed 1,272 deliveries by 1 obstetrician in a Taiwanese hospital between February 2004 and December 2011. These parturients were nulliparas with singleton pregnancies ≥ 37 weeks gestation who had liveborn cephalic deliveries. The CS group consisted of parturients with dystocia-related CS for the following indications: prolonged latent phase, failure to progress, or arrest of descent. Eight confounding variables [maternal age, height, weight, body mass index (BMI) in labor, gestational age, infant birth weight, gender, and cervical dilatation] were obtained from the medical records. Multivariate logistic regression analysis was used to determine the association between each variable and route of delivery. A predictive formula for CS probability was generated using a logistic regression model.

RESULTS

Overall 15.0 % of nulliparas in our population underwent CS. Logistic regression analysis revealed a significant association between maternal BMI and CS (adjusted OR 1.112; 95 % CI 1.065-1.161; P < 0.001). The association between maternal age and CS was also statistically significant (adjusted OR 1.074, 95 % CI 1.033-1.116, P = 0.001). Maternal height, weight in labor, gestational age, infant birth weight, gender, and cervical dilatation were not significantly associated with the route of delivery. A predictive formula for CS probability was developed based on a combination of maternal BMI and age.

CONCLUSIONS

Our results show that maternal age and BMI in labor are significantly associated with dystocia-related CS in uncomplicated Taiwanese nulliparas at term. We develop a practical formula to predict the probability for CS. Using this formula, obstetricians can estimate the risk of CS according to maternal age and BMI in labor.