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

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.

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.

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.

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.