Weight loss after diagnosis with gestational diabetes and birth weight among overweight and obese women.

To determine if, among overweight or obese women with gestational diabetes (GDM), weight loss after GDM diagnosis is associated with lower infant birth weight within levels of overweight or obesity class. Overweight and obese women with singleton pregnancies managed for GDM at a large diabetes and pregnancy program located in Charlotte, NC between November 2000 and April 2010, were eligible for this retrospective cohort study. All were managed using a rigorous standardized clinical protocol. Clinical information including maternal pre-pregnancy body mass index, gestational weight gain, treatment, and medical and obstetric history was abstracted from medical records. The association of weight loss after GDM diagnosis and birth weight was analyzed using linear regression stratified by maternal pre-pregnancy overweight or obesity class (I, II/III). Of the 322 women in this study 19 % lost weight between diagnosis of GDM and delivery. After adjustment for maternal age, parity, race/ethnicity, gestational week at first hemoglobin A1c (A1C), A1C at diagnosis, weight gain prior to GDM, treatment with insulin or oral hypoglycemic agents, gestational age at delivery, and infant sex, weight loss was associated with 238.3 g lower mean infant birth weight among overweight women (95 % CI -393.72, -82.95 g), but was not associated with lower mean infant birth weight among obese class II/III women (95 % CI -275.61, 315.38 g). Weight loss, after diagnosis of GDM, is associated with lower infant birth weight among overweight women, but not among obese class II/III women.