Maternal overweight and obesity and its association with metabolic changes and fetal overgrowth in the absence of gestational diabetes mellitus: A prospective cohort study

Introduction Previous studies indicated an association between fetal overgrowth and maternal obesity independent of gestational diabetes mellitus (GDM). However, the underlying mechanisms beyond this possible association are not completely understood. This study investigates metabolic changes and their association with fetal and neonatal biometry in overweight and obese mothers who remained normal glucose‐tolerant during gestation. Material and methods In this prospective cohort study 893 women who did not develop GDM were categorized according to their pregestational body mass index (BMI): 570 were normal weight, 220 overweight and 103 obese. Study participants received a broad metabolic evaluation before 16 weeks and were followed up until delivery to assess glucose levels during the oral glucose tolerance test (OGTT) at mid‐gestation as well as fetal biometry in ultrasound and pregnancy outcome data. Results Increased maternal BMI was associated with an adverse metabolic profile at the beginning of pregnancy, including a lower degree of insulin sensitivity (as assessed by the quantitative insulin sensitivity check index) in overweight (mean difference: −2.4, 95% CI −2.9 to −1.9, p