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 h/night in early pregnancy, those who slept <7 h/night showed a higher risk of GDM (OR, 1.75; 95 % CI: 1.20–2.54), whereas those who slept >9 h/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.