Obesity as a risk factor for failed trial of labor in patients with previous cesarean delivery

OBJECTIVE: This study was undertaken to determine whether obesity is a risk factor for failed trial of labor (TOL) in women with previous cesarean delivery (CD). STUDY DESIGN: We performed a review of singleton gestations 36 weeks or greater with previous CD who underwent TOL from January 1998 to June 2002, stratifying by body mass index (BMI, kg/m2): normal (BMI <25), overweight (BMI 25-29.9), obese (BMI 30-39.9), and morbidly obese (BMI >40). Rates for failed TOL were determined, and groups compared. RESULTS: For 725 patients, failed TOL rates were as follows: 14.1%, 20.4%, 27.7%, and 30.3% for normal, overweight, obese, and morbidly obese groups, respectively (P < .0001). Significant risk factors included: no previous vaginal delivery, labor induction, recurrent CD indication, and fetal macrosomia. However, obesity remained an independent risk factor for failed TOL in the obese and morbidly obese groups with odds ratio of 1.99 (95% CI 1.20-3.30) and 2.22 (1.11-4.44) for these groups (P = .03), respectively. CONCLUSION: Obesity is an independent risk factor for failed TOL in patients with previous CD.