Mean maternal BMI was 27.7, 13.7%were obese(BMI $33.0kg/m2), and GDM was diagnosed in 16.1%.Relative to non-GDM and non obese women,odds ratio for birth weight .90th percentile for GDM a lone was 2.19(1.93–2.47),for obesity alone 1.73(1.50–2.00),and for both GDM and obesity 3.62 (3.04–4.32). Results for primary cesarean delivery and preeclampsia and for cord C-peptide and newborn percent body fat. 90th percentiles were similar.Odds for birth weight.90th percentile were progressively greater with both higher OGTT glucose and higher maternal BMI.There was a 339-g difference in birth weight for babies of obese GDM women, compared with babies of normal/under weight women(64.2% of all women) with normal glucose based on a composite OGTT measure of fasting plasma glucose and 1- and 2-h plasma glucose values (61.8% of all women).