Folate, vitamin B12 implicated in gestational diabetes

Women with elevated red blood cell (RBC) folate and vitamin B12 concentrations in early pregnancy are at risk of developing gestational diabetes mellitus (GDM), a study has found.

The analysis used data from 1,058 pregnant women (mean age, 30.24 years; mean body mass index, 21.03 kg/m²) included within the Shanghai Preconception Cohort Study. RBC folate and vitamin B12 measurements were conducted at recruitment (between 9 and 13 gestational weeks), and all women contributed three blood samples for glucose measurements under oral glucose tolerance test.

Of the women, 38.75 percent had a family history of diabetes, 15.60 percent reported smoking exposure, and 13.42 percent consumed alcohol during gestation. Most of the women (63.7 percent) received folic acid supplements, with most of them taking compound vitamin supplements. The median concentrations of RBC folate, serum folate, and vitamin B12 were 385.92 ng/mL, 14.39 ng/mL, and 405.93 pg/mL, respectively.

Between 24 and 28 weeks of gestation, 180 cases (17.01 percent) of GDM occurred. RBC folate and vitamin B12 levels were significantly higher in women with versus without GDM (p=0.045 and p=0.002, respectively) and positively correlated with 1-h and 2-h serum glucose.

Multivariable logistic regression analyses revealed that daily folic acid supplementation in early pregnancy contributed to increased GDM risk (odds ratio [OR], 1.73, 95 percent confidence interval [CI], 1.19–2.53; p=0.004). RBC folate ≥600 versus <400 ng/mL levels were associated with about 1.6-fold higher odds of GDM (OR, 1.58, 95 percent CI, 1.03–2.41; p=0.033).

Likewise, vitamin B12 showed a positive association with GDM risk (per 100 pg/mL: OR, 1.14; p=0.002).

There was no significant association seen between GDM and serum folate and percentile ratio of RBC folate/vitamin B12.

More studies are needed to determine the appropriate levels of folate and vitamin B12 in early pregnancy that are essential for maternal and offspring health.