Advances in studies on gestational diabetes reveals more factors associated with GDM risks. In this line, a study published in Diabetes Care investigated the association of folate and vitamin B12 in early pregnancy with GDM risk. The study cohort were a total of 1,058 pregnancies with red blood cell (RBC) folate and vitamin B12 measurements at recruitment (between 9 and 13 gestational weeks) and those with three samples available for glucose measurements under oral glucose tolerance test. GDM was diagnosed between 24 and 28 weeks’ gestation. Odds ratio (OR) of having a GDM and 95% CI was used to quantify the association.

      The outcomes of the study revealed that RBC folate and vitamin B12 were significantly higher in pregnancies with GDM than those without GDM (P values were 0.045 and 0.002, respectively) and positively correlated with 1-h and 2-h serum glucose. The supplementation of daily folic acid in early pregnancy also increases the risk of GDM; OR (95% CI) was 1.73 (1.19–2.53) (P = 0.004). Compared with RBC folate <400 ng/mL, pregnancies with RBC folate ≥600 ng/mL were associated with ~1.60-fold higher odds of GDM; the adjusted OR (95% CI) was 1.58 (1.03–2.41) (P = 0.033). The study also showed a significant association between Vitamin B12 GDM risk (OR 1.14 per 100 pg/mL; P = 0.002).

      The study concluded that there is a remarkable association between higher maternal RBC folate, vitamin B12 levels in early pregnancy and GDM risk and the balance of folate/vitamin B12 is not significantly associated with GDM.