Association between nighttime sleep duration, midday napping, and sleep quality during early pregnancy and risk of gestational diabetes mellitus: A prospective cohort study in China

Aim: To evaluate the prospective associations of nighttime sleep duration, midday napping, and sleep quality during early pregnancy with gestational diabetes mellitus (GDM) risk among Chinese pregnant women. Methods: Sleep-related information was assessed by the Pittsburgh Sleep Quality Index in baseline surveys during the 6 -15 (mean 10.3) gestational weeks. GDM was diagnosed during 24 -28 gestational weeks according to the Chinese Guidelines on Diagnosis and Management of Hyperglycemia in Pregnancy (2022). Multivariable logistic regression models with adjustments for socio-demographic and lifestyle factors were used to estimate odds ratios (ORs) and 95 % confidence intervals (CIs) for the associations of sleep traits with GDM risk. Results: We identified 503 incident GDM cases among 6993 participants. Compared with women who slept for 7 -9 hours/night in early pregnancy, those who slept <7 hours/night showed a higher risk of GDM (OR, 1.75; 95 % CI: 1.20 -2.54), whereas those who slept >9 hours/night showed no significant association for GDM risk (OR, 1.01; 95 % CI: 0.78 -1.30). Compared with women with absolutely no napping, those with <= 60 and > 60 min/ day midday napping showed no significant association for GDM risk (OR, 0.82; 95 % CI: 0.64 -1.05 for <= 60 min/ day midday napping; OR, 0.87; 95 % CI: 0.66 -1.15 for >60 min/day midday napping). Poor sleep quality was not associated with GDM risk compared with good quality (OR, 0.90; 95 % CI: 0.72 -1.12). Conclusion: A short nighttime sleep duration during early pregnancy was associated with a higher risk of GDM, which was independent of midday napping, sleep quality and lifestyle factors.