Sleep Patterns During Pregnancy, Genetic Susceptibility and Progression From Gestational Diabetes Mellitus to Postpartum Glucose Intolerance: A Prospective Cohort Study

AIMS: Gestational diabetes mellitus (GDM) is related to postpartum glucose intolerance (PGI) and future type 2 diabetes mellitus (T2DM). Sleep is a modifiable factor, yet its role in the GDM-to-PGI progression and its interaction with genetic susceptibility remain uncertain. We examined relationships between prenatal sleep patterns and PGI risk and their joint effects with genetic risk among women with GDM. MATERIALS AND METHODS: This prospective cohort study recruited 897 women with GDM in Guangzhou, China (2022-2024). A healthy sleep score was constructed by integrating prenatal sleep duration, chronotype, sleep quality and midday napping. Polygenic risk score was calculated using 154 T2DM-associated variants. PGI was ascertained via a 75-g oral glucose tolerance test at 4-12 weeks postpartum. Modified Poisson and linear regression models were used. RESULTS: Overall, 255 women (28.4%) developed PGI. Women with intermediate or healthy sleep patterns during pregnancy exhibited lower PGI risk compared with those with an unhealthy sleep pattern, with relative risks of 0.77 (95% confidence interval [CI]: 0.61, 0.98) and 0.70 (95% CI: 0.54, 0.92), respectively. A healthy sleep pattern was also related to lower postpartum fasting glucose (β: -0.158; 95% CI: -0.239, -0.078) but not 2-h glucose. The highest PGI risk was observed among women with an unhealthy sleep pattern and high genetic risk. CONCLUSIONS: A healthy prenatal sleep pattern was related to a lower PGI risk among women with GDM, regardless of genetic susceptibility. Promoting healthy sleep behaviours during pregnancy may help improve early postpartum glycaemic outcomes in this high-risk population.