Low Vitamin B12 Levels in Early Pregnancy Are Associated with Fasting Glycemia—A Prospective Cohort Study

Abstract

Background: The pathogenesis of gestational diabetes mellitus (GDM) is not fully understood and combining novel biomarkers with established risk factors could improve early prediction of GDM. Low vitamin B12 (B12) levels have been linked to obesity, insulin resistance and GDM but its predictive ability in early pregnancy as a risk factor for later GDM has not been proven. Methods: Micronutrients in Pregnancy as a Risk factor for gestational diabetes and Effects on mother and baby (PRiDE) is a cohort study of pregnant women at high risk of developing GDM (n=4751 recruited). GDM was diagnosed by a 2-hour 75g OGTT according to UK NICE criteria (fasting blood glucose, FBG ≥5.6mmol/l or 2-hour BG ≥7.8mmol/l). B12 and folate were measured by electrochemiluminescence and deficiency defined as ≤200pg/ml and ≤3ng/ml respectively. Multiple linear and logistic regression models were done with covariates including age, BMI, ethnicity, parity, smoking status, gestational weight gain and folate levels. Results: The data from the first 3412 women with complete B12/folate and OGTT results were analysed (median (range) gestational age 12+5(4+3, 16+0) and 26+4 (15+0, 32+1) weeks respectively). Mean (±SD) age was 30.7±5.2 years, BMI 30.8±7.3 kg/m2 and 56.0% were obese. 11.5% had GDM and B12 and folate deficiency rates were 10.2% and 0% respectively (p>0.05 in GDM vs. no-GDM). GDM women had similar B12 and folate values to no-GDM (346±151 vs. 357 ± 155 pg/ml and 19.8±12.6 vs. 18.8±12.1 ng/ml respectively, adjusted p>0.05). B12 was negatively correlated with BMI (Pearson’s r=-0.24, p<0.001) and inversely related to FBG, after adjustment for covariates including BMI (β=-0.03, p=0.003). There was no association with 2-hour BG. Low B12 values were more predictive of GDM among obese women (mean 314±119 vs. 328±134 pg/ml, adjusted p=0.06). Conclusions: Early pregnancy B12 values were predictive of high FBG in late gestation. Low B12 levels may be an independent risk factor for GDM, particularly in obese women. Disclosure N. Sukumar: None. A. Antonysunil: None. Y. Ghebremichael-Weldeselass: None. I. Goljan: None. C. Bagias: None.