Effects of sleep duration and sleep quality in early pregnancy and their interaction on gestational diabetes mellitus

To examine the association of sleep duration and quality in early pregnancy with gestational diabetes mellitus (GDM), and explore their interaction effect on GDM. Participants from 2 hospitals were enrolled in this case–control study between April 2018 and November 2020. Sleep duration and quality were measured using the Pittsburg Sleep Quality Index (PSQI). A total of 1300 participants (396 GDM and 904 controls) were included. After adjusting for potential confounders, higher global PSQI scores or poor sleep quality were associated with GDM with odds ratios of 1.13 (95% CI 1.07, 1.19, p < 0.001) and 1.75 (95% CI 1.29, 2.38, p < 0.001), respectively; sleep duration < 7 h, 9–9.9 h and ≥ 10 h were all associated with increased GDM with odds ratios of 4.28 (95% CI 2.51, 7.31, p < 0.001), 1.69 (95% CI 1.20, 2.39, p = 0.003), and 4.42 (95% CI 3.01, 6.50, p < 0.001), respectively. In the stratified analysis based on sleep duration, the effect of poor sleep quality on GDM in the < 7 h group (OR 5.47, 95% CI 2.57, 11.64, p < 0.001) was much stronger than that in the 7–8.9 h group (OR 1.24, 95% CI 0.81, 1.91, p = 0.327), and the p value of the interaction was 0.011. Poor sleep quality and short or long sleep duration in early pregnancy were all associated with GDM, and an interaction effect between short sleep duration and poor sleep quality on GDM was noted.