Objective
To determine whether maternal body mass index (BMI) influences the beneficial effects of diabetes treatment in women with gestational diabetes (GDM).
Study Design
Secondary analysis of a multicenter randomized treatment trial of women with GDM. Outcomes of interest were elevated umbilical cord c-peptide levels (>90th percentile 1.77 ng/mL), LGA birth weight (>90th percentile), and neonatal fat mass (g). Women were grouped into five BMI categories adapted from the WHO International Classification of normal, overweight, and obese adults. Outcomes were analyzed according to treatment group assignment.
Results
A total of 958 women were enrolled (485 treated and 473 controls). Maternal BMI at enrollment was not related to umbilical cord c-peptide levels. However, treatment of women in the overweight, Class I, and Class II obese categories was associated with a reduction in both LGA birth weight and neonatal fat mass. Neither measure of excess fetal growth was reduced with treatment in normal weight (BMI <25) or Class III (BMI ≥ 40) obese women.
Conclusion
There was a beneficial effect of treatment on fetal growth in women with mild GDM who were overweight or Class I and II obese. These effects were not apparent for normal weight and very obese women.