Vitamin B12 Status among Pregnant Women in the UK and Its Association with Obesity and Gestational Diabetes

Abstract

Background: To evaluate vitamin B12 and folate status in pregnancy and their relationship with maternal obesity, gestational diabetes mellitus (GDM), and offspring birthweight. Methods: A retrospective case-control study of 344 women (143 GDM, 201 no-GDM) attending a district general hospital and that had B12 and folate levels measured in the early 3rd trimester was performed. Maternal history including early pregnancy body mass index (BMI) and neonatal data (birthweight, sex, and gestational age) was recorded for all subjects. Results: 26% of the cohort had B12 levels <150 pmol/L (32% vs. 22% in the two groups respectively, p < 0.05) while 1.5% were folate deficient. After adjusting for confounders, 1st trimester BMI was negatively associated with 3rd trimester B12 levels. Women with B12 insufficiency had higher odds of obesity and GDM (aOR (95% CI) 2.40 (1.31, 4.40), p = 0.004, and 2.59 (1.35, 4.98), p = 0.004, respectively), although the latter was partly mediated by BMI. In women without GDM, the lowest quartile of B12 and highest quartile of folate had significantly higher adjusted risk of fetal macrosomia (RR 5.3 (1.26, 21.91), p = 0.02 and 4.99 (1.15, 21.62), p = 0.03 respectively). Conclusion: This is the first study from the UK to show that maternal B12 levels are associated with BMI, risk of GDM, and additionally may have an independent effect on macrosomia. Due to the increasing burden of maternal obesity and GDM, longitudinal studies with B12 measurements in early pregnancy are needed to explore this link.

Joint effects of folate and vitamin B12 imbalance with maternal characteristics on gestational diabetes mellitus

“…The findings of this study are consistent with previous studies showing that a low vitamin B 12 concentration may be an independent risk factor for GDM. [10][11][12] The above findings of the present and previous studies show that high folate and low vitamin B 12 can interfere with the onset of GDM. Therefore, a new indicator, the folate: vitamin B 12 ratio, representing high folate and/or low vitamin B 12 , was calculated to explore the effects of B vitamin imbalance on GDM risk.…”

“…[6][7][8][9] Recently, the role of folate and vitamin B 12 on the development of GDM has emerged as a field of interest. [10][11][12] Folate and vitamin B 12 are metabolically entwined during 1-carbon metabolism. Both serve as cofactors in the synthesis of methionine from homocysteine (Hcy).…”

“…15,17 Recent studies from India and the UK suggest that maternal vitamin B 12 deficiency is associated with GDM in pregnant women. 10,11 Furthermore, the incidence of GDM increased with folate concentrations among vitamin B 12 -deficient women. 10 Meanwhile, a cohort study in China indicated that folic acid consumption in early pregnancy may increase the risk of GDM.…”

Association of maternal folate status in the second trimester of pregnancy with the risk of gestational diabetes mellitus

“…However, a few studies reported that serum folate concentrations were not associated with GDM risk (Krishnaveni et al, 2009;Sukumar et al, 2016). For example, Sukumar et al (2016) Note: Values are expressed as numbers with percentages (%). All values are ORs (95% CIs) and adjusted for maternal age, BMI at enrollment, gestational weeks at enrollment, gestational weeks at delivery, and infant gender (excluded the stratified factor in each stratum) critical time windows in pregnancy make comparisons challenging.…”

Vitamin B12 status in kidney transplant recipients: association with dietary intake, body adiposity and immunosuppression

“…authors (14)(15)(16)(17)(18)(19)(20)(21) . However, to date, no study has evaluated the association of serum B 12 levels with excessive body weight using a 'gold standard' method to evaluate body adiposity such as dual-energy X-ray absorptiometry (DXA).…”