Associations of BMI and OGTT glucose measures with pregnancy outcomes in risk-based screening for GDM

BACKGROUND: Gestational diabetes mellitus (GDM) arises from increasing insulin resistance during pregnancy combined with inadequate pancreatic β-cell adaptation and is associated with adverse pregnancy outcomes. Obesity and maternal hyperglycemia contribute to these risks, yet GDM is increasingly recognized as a heterogeneous condition. We evaluated whether pre-pregnancy BMI and oral glucose tolerance tests (OGTT)-derived fasting (FPG) and 2-hour glucose values show distinct associations with adverse pregnancy outcomes in a risk-based screened cohort. MATERIAL AND METHODS: We performed a post-hoc analysis of 4,431 OGTTs (2011-2016) from a Dutch risk-based screening cohort. Outcomes were described across predefined BMI and glucose categories, followed by multivariable logistic regression with BMI, FPG measured at the time of OGTT, and 2-hour glucose entered simultaneously and additionally adjusted for treatment status. Eight clinical subgroups combining BMI with fasting and 2-hour glucose thresholds were also explored. RESULTS: Higher BMI was mainly associated with hypertensive disorders of pregnancy and cesarean delivery. Higher FPG levels showed the broadest associations, including adverse maternal, delivery and neonatal outcomes. Higher 2-hour post-load glucose levels were primarily associated with fetal growth-related outcomes and neonatal hypoglycemia. Adjustment for treatment attenuated some 2-hour glucose-related associations but did not materially affect BMI- or FPG-related risks. CONCLUSIONS: In women undergoing OGTT because of risk factors or clinical suspicion of GDM, pre-pregnancy BMI, fasting glucose measured at the time of OGTT, and 2-hour post-load glucose demonstrate distinct patterns of association with adverse pregnancy outcomes. These findings suggest heterogeneous patterns of dysglycemia-related risk, alongside the independent contribution of BMI, in a risk-based screening population.