The Influence of Maternal Folate Status on Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis

Pre-gestational diabetes mellitus, gestational diabetes mellitus, and its association with the MTHFR C677T polymorphism

Gestational diabetes mellitus (GDM) is a common condition during pregnancy and is associated with an increased risk of pre-eclampsia. The methylenetetrahydrofolate reductase (MTHFR) gene plays a crucial role in folate metabolism and has been implicated in GDM. To investigate the relationship between the MTHFR C677T gene polymorphism and the conditions of GDM and gestational prediabetes in pregnant women. A case-control study was conducted in 114 pregnant women with GDM and 96 pregnant women without GDM, from the first trimester to the prenatal examination at Can Tho Obstetrics Hospital. The pregnant women underwent a 1-hour (G1) and 2-hour (G2) oral glucose tolerance test (OGTT) and genetic polymorphism analysis based on real-time PCR technique. In pregnant women with GDM, weight, concentrations of G0, G1, G2, and folic acid were higher than those in the non-GDM group, with P < .05. When analyzing the subgroup without gestational diabetes, we found that the rate of prediabetes was 16.6% (16/96 pregnant women). In this group, blood glucose levels at 1 hour and 2 hours during the OGTT were higher compared to the normal glucose group (P < .05). A 2-hour post-OGTT glucose level of 7.78 mmol/L had a sensitivity of 93.8%, a specificity of 100%, and an area under the curve of 0.987 for diagnosing gestational prediabetes (P < .001). However, there were no statistically significant differences in the CC, CT, and TT polymorphisms of the MTHFR C677T gene among pregnant women with or without pre-gestational and GDM. Both fasting blood glucose and 2-hour glucose concentrations during the OGTT, as well as folic acid concentrations, were higher in both the pre-gestational and GDM groups compared to the non-gestational diabetes cohort. However, the analysis of MTHFR C677T polymorphisms revealed no statistically significant differences among the groups, highlighting the necessity for more extensive investigations to gain deeper insights into this relationship.

Association of serum folic acid levels in response to fasting blood glucose in early pregnancy with the risk of gestational diabetes mellitus: A retrospective cohort study

OBJECTIVE

With increasingly prevalent folic acid consumption in early pregnancy, concerns about its potentially negative effect on maternal metabolism have been raised. Recent findings regarding folic acid levels in the first trimester and the risk of gestational diabetes mellitus have been inconclusive. The aim of this study was to investigate the association of folic acid status in early pregnancy with gestational diabetes mellitus as well as examine whether glucose levels can be modulated by folic acid status during the same first trimester.

METHODS

This was a retrospective cohort study based on 27 128 Chinese pregnant women who registered during their first prenatal visit from January 2015 to December 2019. Serum folic acid and fasting blood glucose concentrations were measured during the 9th to 13th gestational weeks. Binary logistic regression was applied to estimate the odds ratios of gestational diabetes mellitus by using the serum folic acid levels quartiles with adjustment for major confounders. To investigate the potential effect of modifying key risk factors for gestational diabetes mellitus, we established subgroups, in which analyses were stratified by age (<25, 25-29, 30-34, and ≥35 y), parity (nulliparous and parous), prepregnancy body mass index (< 18.5, 18.5-23.9, and ≥ 24 kg/m2), and family history of diabetes (yes and no).

RESULTS

The positive association between maternal folate concentrations and fasting blood glucose was observed: the risk for hyperglycemia was higher in those in the middle (Q3) and higher (Q4) quartiles compared with those in Q1 and Q2. A higher risk for gestational diabetes mellitus was found in hyperglycemia of early pregnant women with high folate concentrations (Q3: odds ratio = 5.63; 95% CI, 4.56-6.95, and Q4: odds ratio = 5.57; 95% CI, 4.68-6.64) compared with normal fasting glucose mothers with folate concentrations in Q1 and Q2 after accounting for multiple covariables. Similar patterns were observed for different subgroups. Restricted cubic spline plots had a positive correlation of serum folic acid level with fasting blood glucose concentration as well as risk of gestational diabetes mellitus in a nonlinear pattern, with 32.5 nmol/L as the cutoff point for folic acid level.

CONCLUSIONS

Our findings underscore the importance of maintaining an appropriate folic acid concentration for preserving a lower risk of gestational diabetes mellitus, especially in women with relatively higher blood glucose in early pregnancy. Additionally, folic acid concentration > 32.5 nmol/L may be considered a risk factor for gestational diabetes mellitus. This research suggested that folic acid levels should be monitored during the first trimester from the first prenatal checkup to prevent adverse effects of excessive folic acid intake.

Gestational diabetes mellitus is associated with distinct folate-related metabolites in early and mid-pregnancy: A prospective cohort study

AIMS

This study aimed to evaluate the association between gestational diabetes mellitus (GDM) and circulating folate metabolites, folic acid (FA) intake, and the methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) genotype.

MATERIALS AND METHODS

A prospective pregnancy cohort study was conducted in Beijing, China, from 2022 to 2023. Circulating folate metabolites, including red blood cell (RBC) 5-methyltetrahydrofolate (5-MTHF), 5, 10-methylene-tetrahydrofolate (5,10-CH2-THF), 5- formyltetrahydrofolate (5-CHO-THF), and unmetabolised folic acid (UMFA), and plasma homocysteine (HCY), 5-MTHF, and methylmalonic acid (MMA), were determined at 6-17 weeks and 20-26 weeks of gestation. FA intake and the MTHFR and MTRR genotype were also examined. GDM was diagnosed between 24 and 28 weeks of pregnancy by a 75-g oral glucose tolerance test (OGTT). The association between the folate status and GDM was ascertained using multivariate generalised linear models, logistic regression models, and restricted cubic spline regression, adjusting for potential confounders.

RESULTS

The study included 2032 pregnant women, of whom 392 (19.29%) developed GDM. UMFA above the 75th percentile (≥P75) [adjusted OR (aOR) (95% confidence interval [CI]) = 1.36 (1.01-1.84)], UMFA ≥ P90 [aOR (95% CI) = 1.82 (1.23-2.69)], and HCY ≥ P75 [aOR (95% CI) = 1.40 (1.04-1.88)] in early pregnancy, and RBC 5-MTHF [aOR (95% CI) = 1.48 (1.10-2.00)], RBC 5,10-CH2-THF [aOR (95% CI) = 1.55 (1.15-2.10)], and plasma 5-MTHF [aOR (95% CI) = 1.36 (1.00-1.86)] in mid-pregnancy ≥ P75 are associated with GDM. Higher UMFA levels in early pregnancy show positive associations with the 1-h and 2-h glucose levels during the OGTT, and higher HCY levels are associated with increased fasting glucose levels during the OGTT. In comparison, RBC 5- MTHF and 5,10-CH2-THF, and plasma 5- MTHF in mid-pregnancy are positively associated with the 1-h glucose level (p < 0.05). The MTHFR and MTRR genotype and FA intake are not associated with GDM.

CONCLUSIONS

Elevated levels of UMFA and HCY during early pregnancy, along with elevated RBC 5-MTHF and 5,10-CH2-THF and plasma 5-MTHF during mid-pregnancy, are associated with GDM. These findings indicate distinct connections between different folate metabolites and the occurrence of GDM.

Nutrients as Risk Factors and Treatments for Gestational Diabetes

Gestational diabetes (GDM), traditionally defined as any form of glucose intolerance first detected in pregnancy [...].