LEP and preeclampsia: Bishop score (OR 1.5, P < 0.001), BMI (OR 0.92, P < 0.001), preeclampsia (0.12, P = 0.01), use of multiple methods of induction (OR 0.22, P = 0.008) and leptin (OR 0.42, P = 0.02) were the only covariates significantly associated with successful IOL.