Associations of Serum Selenium Levels in the First Trimester of Pregnancy with the Risk of Gestational Diabetes Mellitus and Preterm Birth: a Preliminary Cohort Study.

Women with gestational diabetes mellitus (GDM) may have lower serum selenium levels than healthy controls, which may be associated with preterm birth. We explored the association of serum selenium levels in early pregnancy with the risk of GDM and preterm birth among Chinese women. We included 398 women with a singleton pregnancy, who were followed up prospectively from the first prenatal visit until delivery. Serum selenium levels were measured in the first trimester. After delivery, data concerning mothers and their children were sourced from medical records by researchers who were blind to the participants' selenium status. Of the 398 women, 71 (17.8%) had GDM, 21(5.3%) had preterm birth, and 266 (66.8%) had selenium deficiency (serum selenium < 70 μg/L). Women in the upper three quartiles of serum selenium level did not have a significantly lower risk of GDM or preterm birth than those in the lowest quartile after adjustment for covariates (all p > 0.05). When serum selenium levels were classified as normal or deficient, the risk of GDM or preterm birth among women with normal serum selenium levels was still not lower than that of women with deficient serum selenium levels after adjustment for covariates (all p > 0.05). Although selenium deficiency was common in the Chinese women in our cohort, our results indicate that low serum selenium level during early pregnancy may not be a strong predictor of the risk of GDM and preterm birth. However, our sample size was small, and future studies with larger populations are warranted.