Association of maternal vitamin B12 and folate levels in early pregnancy with gestational diabetes : a prospective UK cohort study (PRiDE study)

OBJECTIVE To investigate the association of folate and vitamin B12 in early pregnancy with gestational diabetes mellitus (GDM) risk. RESEARCH DESIGN AND METHODS The data of this study were from a subcohort within the Shanghai Preconception Cohort Study. We included 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 an oral glucose tolerance test. GDM was diagnosed between 24 and 28 weeks’ gestation. Odds ratio (OR) and 95% CI of having GDM was used to quantify the association. RESULTS A total of 1,058 pregnant women were included, and GDM occurred in 180 (17.01%). 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. Daily folic acid supplementation in early pregnancy increases the risk of GDM; OR (95% CI) was 1.73 (1.19–2.53) (P = 0.004). Compared with RBC folate