Association of gestational weight gain with cesarean delivery rate after labor induction.

OBJECTIVE To evaluate the association of gestational weight gain with the cesarean delivery (CD) rate in term women undergoing induction of labor (IOL). STUDY DESIGN This is a retrospective cohort study of 2,495 consecutive term women from May 2005 to June 2008 admitted for IOL between 37 and 42 completed weeks of gestation. Labor induction ending in cesarean delivery was defined as a binary outcome. Weight gain during pregnancy was calculated by subtracting prepregnancy weight from weight recorded at delivery. Multiple gestation, malpresentation, stillbirth, planned CD and women with prior CD were excluded. Maternal and obstetric characteristics were examined as predictors of CD using multivariable logistic regression analyses. RESULTS The risk of CD increased by 13% (odds ratio [OR] 1.13, 95% confidence interval [CI] 1.05-1.23) for each 5 kg increase in gestational weight gain. Other factors associated with an increased risk of CD included maternal age (OR per year 1.05, 95% CI 1.03-1.06), neonatal birth weight (OR 1.06 per 100 g, 95% CI 1.03-1.08), nulliparity (OR 9.13, 95% CI 7.00-11.90), Bishop score at admission < or = 5 (OR 2.3, 95% CI 1.90-2.90), male infant (OR 1.37, 95% CI 1.10-1.70) and unit increase in prepregnancy body mass index (OR 1.08, 95% CI 1.06-1.10). CONCLUSION The CD rate following labor induction increases significantly with increasing gestational weight gain even after controlling for possible confounding variables.