As cohort studies of the impact of sleep duration during early pregnancy on gestational diabetes mellitus (GDM) are lacking, our study aimed to explore the association between sleep duration in the first trimester and GDM in one region of mainland China.

For this prospective cohort study, sleep duration data were collected from 3692 pregnant women at the first prenatal care appointment before 14 weeks of gestation. Multivariable log-binomial regression models were used to analyze the association of sleep duration with GDM after adjusting for demographic characteristics, health status (such as family history of diabetes, history of GDM, prepregnancy body mass index, gestational weight gain) and lifestyle habits (such as physical activity, dietary intakes).

Our cohort included 166 (4.5%) short sleepers and 505 (14%) long sleepers. Shorter sleep duration was more likely to be observed in women aged ≥35 years who were multiparous, and had previous pregnancy, insufficient gestational weight gain, engaged in more vigorous physical activity, drank alcohol, were vegan and/or never took folic-acid supplements. Compared with normal sleepers (29%), the prevalence of GDM was significantly higher in short sleepers (38%; P = 0.01), but not in long sleepers (31%; P = 0.224). In the multivariable model, women with short sleep durations during early pregnancy had a 32% greater risk of GDM [adjusted risk ratio (aRR): 1.32, 95% CI: 1.06–1.63], whereas long sleepers did not (aRR: 1.09, 95% CI: 0.94–1.26).

Short sleep duration during early pregnancy is associated with an increased risk of GDM. This suggests that more attention should be paid to controlling the development of GDM in pregnant women with insufficient sleep.