Background: Genetic determinants of glycemic regulation in pregnancy are poorly understood.

Methods: We studied 35 glycemia-related traits measured during pregnancy and 191 genetic variants identified in prior genome-wide association studies of type 2 diabetes (T2D) or gestational glycemia. Using linear regression, we quantified associations between glucose-raising alleles and traits measured in 582 women at 24-28 weeks gestation. We clustered traits and variants using Bayesian nonnegative matrix factorization (bNMF) to identify physiologic pathways involved in pregnancy glucose metabolism.

Results: In a plurality of bNMF iterations (22/50), 5 clusters emerged, with highly weighted traits and loci suggesting distinct physiologic pathways. Cluster 1: reduced insulin secretory response (lower insulin/c-peptide, greater insulin sensitivity); loci included several known or suspected to affect beta-cell function (ABO, CDKN2B, SLC30A8, CDKN1B). Cluster 2: obesity-related hyperglycemia (higher percent body fat, BMI, fasting/post-load glucose); loci included known obesity/T2D loci (MCR4, FTO) and loci previously tied to beta-cell function that associated with higher glucose and greater adiposity pregnant women (MTNR1B, GLP2R). Cluster 3: insulin resistance (reduced insulin sensitivity, higher fasting insulin/c-peptide, greater insulin secretory response); loci included LYPLAL1 and ANKRD55 (known to harbor insulin resistance variants). Cluster 4 traits suggested reduced adiposity with post-load glucose intolerance. Cluster 5 traits suggested a favorable metabolic profile (lower cholesterol and glucose, higher disposition index and insulin sensitivity).

Conclusion: Genetic variants can be grouped to identify physiologic mechanisms at play in gestational glycemic regulation. Associations between physiologically-informed variant clusters, gestational diabetes, and related perinatal outcomes await testing in well-powered cohorts.


C.E. Powe: None. M. Udler: None. C. Allard: None. J. Kim: None. P. Perron: None. L. Bouchard: None. J.C. Florez: None. M. Hivert: None.


American Diabetes Association/Pathway to Stop Diabetes (1-15-ACE-26 to M-F.H.); National Institute of Diabetes and Digestive and Kidney Diseases (K23DK113218, K24DK110550); Robert Wood Johnson Foundation; Fonds de la recherche du Québec en santé

Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at