Gestational diabetes mellitus (GDM) is diagnosed solely on glucose criteria, yet metabolic heterogeneity within this population may influence pregnancy outcomes. In an observational study published in Diabetes, nontargeted metabolomics was used to profile the circulating metabolome of 2,050 pregnant women during midpregnancy to determine whether distinct metabolic signatures were associated with adverse birth outcomes.

The analysis identified 30 metabolites that defined a gestational diabetes metabolic signature (mGDM). Participants were stratified into four metabolic-glycemic groups: normoglycemic non-mGDM, hyperglycemic non-mGDM, normoglycemic mGDM, and hyperglycemic mGDM. Associations with preterm birth, large for gestational age, congenital malformations, and neonatal intensive care unit (NICU) admission were assessed using odds ratios.

Compared with normoglycemic non-mGDM, normoglycemic mGDM was associated with nearly twofold higher odds of preterm birth (OR 1.93; 95% CI, 1.02–3.65) and large for gestational age (OR 2.11; 95% CI, 1.53-2.92). The hyperglycemic non-mGDM group did not show elevated risks compared with the normoglycemic group. The hyperglycemic mGDM profile was associated with higher odds of preterm birth (OR 2.37; 95% CI, 1.04-5.39), large for gestational age (OR 2.28; 95% CI, 1.50-3.47), congenital malformations (OR 1.87; 95% CI, 1.03-3.39), and NICU admission (OR 1.69; 95% CI, 1.09-2.61). A graded increase in risk across the four categories was observed.

In this metabolomics-based observational analysis, metabolic subtypes of GDM were differentially associated with adverse pregnancy outcomes. These findings indicate that metabolic profiling alongside glucose measures may provide additional context for perinatal risk stratification, while remaining within the scope of observational evidence.