Each participant was interviewed and maternal age, gestational age, reproductive and medical histories, history of fetal macrosomia (birth weight >4000g), outcome of previous pregnancy, and family history of diabetes, history of poly cystic ovarian syndrome (PCO), and history of cesarean section were considered. In all subjects, weight and height were measured on the screening day, while pre-pregnancy weight was asked from each woman. The gestational age was estimated by last menstrual period, confirmed or corrected by ultrasonography.