Sleep regularity and efficiency are associated with nocturnal glycemic control in pregnant women with gestational diabetes.

STUDY OBJECTIVES: Nocturnal glycemic control is a critical component of blood glucose management for pregnant women with gestational diabetes mellitus (GDM). This study aims to investigate the associations of sleep quality with nocturnal glycemic control among GDM participants. METHODS: This study included 1,186 GDM participants with available data from the WeBirth cohort in Hangzhou, China. Sleep quality and blood glucose levels were assessed simultaneously over 14 days using accelerometers and continuous glucose monitoring (CGM) devices. Multivariate linear mixed-effects models were applied to examine the associations of the sleep regularity index (SRI) and sleep efficiency (SE) with CGM-derived nocturnal metrics, adjusting for potential confounders (e.g., maternal age, pre-pregnancy BMI and gestational weeks). RESULTS: Per 1-SD increment in SRI was associated with lower nocturnal glycemic metrics, including coefficient of variation (β = -0.11 SD; 95% CI, -0.13 to -0.08) and time-above-range (β = -0.08 SD; 95% CI, -0.10 to -0.05). SE demonstrated comparable associations with these metrics (coefficient of variation: β = -0.13 SD; 95% CI, -0.16 to -0.11; time-above-range: β = -0.10 SD; 95% CI, -0.12 to -0.08). Further joint analyses indicated that SE exerts an independent, additive effect beyond sleep regularity. Specifically, individuals characterized by both irregular and inefficient sleep exhibited substantially higher mean blood glucose levels compared to those with regular and efficient sleep (β = 0.34 SD; 95% CI, 0.21 to 0.47). CONCLUSION: This study highlights that regular and efficient sleep patterns are independently and jointly associated with more favourable nocturnal glycemic outcomes in pregnant women with GDM.