Effect of folic acid supplementation in the association between short sleep duration and gestational diabetes mellitus

Purpose To examine whether or not folic acid (FA) supplementation may modify the relationships between duration or quality of sleep and gestational diabetes mellitus (GDM) risk. Methods In a case–control study of patients with GDM and controls, mothers were interviewed face-to-face at enrollment. The Pittsburgh Sleep Quality Scale was used to assess duration and quality of sleep during early pregnancy, and information on FA supplementation and covariates was obtained using a semiquantitative questionnaire. Results Among 396 patients with GDM and 904 controls, GDM risk increased by 328% and 148% among women with short (< 7 h) and long (≥ 9 h) sleep durations, respectively, compared to those averaging 7–8.9 h sleep. Mothers with poor sleep quality increased their GDM risk by an average of 75% (all p < 0.05). The effect of short sleep duration on GDM risk was much weaker among women with adequate FA supplementation (taking supplements containing ≥ 0.4 mg FA daily for each day of the first three months of pregnancy) than that among women with inadequate FA supplementation, with a p -value for interaction = 0.003. There were no significant effects of FA on links among long duration and poor quality of sleep with GDM risk. Conclusions Sleep duration and quality in early gestation were related to increased GDM risks. FA supplementation may reduce GDM risk associated with short sleep duration.