The effect of maternal obesity on the rate of failed induction of labor.

OBJECTIVE: The purpose of this study was to quantify the relationship between class of obesity and rate of failed induction of labor.

STUDY DESIGN: Using the Ohio Department of Health's birth certificate database from January 1, 2006, through December 31, 2007, we performed a population-based cohort study that compared failed induction of labor rates between obese and normal-weight women.

RESULTS: The rate of induction is associated with increasing body mass index from 28% in normal-weight women to 34% in class III obese women (body mass index, ≥40 kg/m2). Induction failure rates are also associated with increasing obesity class from 13% in normal-weight women to 29% in class III obese women. Women with class III obesity without a previous vaginal delivery and a macrosomic fetus had the highest rate of failed induction at 80%.

CONCLUSION: Obesity is associated with an increased risk of failed labor induction that appears to be related directly to increasing class of obesity.