Compromised cobalamin status during pregnancy may put both mother and child at risk of deficiency during lactation and subsequent development. We investigated whether changes in cobalamin status during pregnancy are associated with impaired status in the mother and the cord. Plasma cobalamin, methylmalonic acid (MMA), and holotranscobalamin (holoTC) concentrations were determined in 92 women at preconception, 8, 20, and 32 wk of pregnancy, at labor, and in the cord. All variables [geometric mean percentiles 10, 90 (P₁₀, P₉₀)] were significantly reduced from preconception [cobalamin: 293 (155, 535) pmol/L; holoTC: 63 (38,98) pmol/L; MMA: 0.12 (0.09, 0.17) μmol/L] by 20 wk of pregnancy [cobalamin: 230 (123, 432) pmol/L; holoTC: 48 (34,78) pmol/L; MMA: 0.11 (0.08, 0.15) μmol/L P < 0.001]. Plasma cobalamin and holoTC remained lower throughout the remainder of pregnancy [32 wk: 198 (107, 339); labor: 224 (117, 444); P < 0.001] and [32 wk: 45 (26,82); labor: 40 (23,79); P < 0.05], respectively. By 32 wk, MMA was greater than preconception [0.14 (0.09, 0.20) μmol/L; P < 0.01]. Plasma holoTC at 32 wk and at labor was negatively correlated with cord MMA (r = −0.51, P < 0.001 and r = −0.40, P < 0.01, respectively). Women with lower holoTC at preconception had greater increases in MMA at 32 wk and at labor. Maternal MMA at 32 wk and at labor was significantly and independently associated with cord MMA only in women with lower holoTC at preconception (regression models: R² = 0.707, 0.682, respectively; P < 0.01). The moderate increases observed in the cobalamin biomarker, MMA, during pregnancy may indicate a functional depletion in intracellular cobalamin status.

Cobalamin deficiency can lead to several adverse health consequences: folate trapping in the methylation cycle and subsequent impaired DNA biosynthesis; pernicious anemia hematologically, similar to that caused by folate deficiency; elevated blood homocysteine (tHcy) (risk factor for cardiovascular disease and adverse pregnancy outcomes); and neural tube defects (NTDs). Population-wide folate status is expected to improve where folic acid fortification policies for reducing NTD occurrence are established. However, there is concern that cobalamin deficiency and its characteristic neuropathy could be masked when hematological abnormalities in risk groups such as the elderly and vegetarians are reversed through folic acid supplementation. Folate-cobalamin interactions and their impact on health are reviewed here.

DNA methylation is an epigenetic phenomenon that can modulate gene function by up or downregulation of gene expression. Vitamin B12 and folate pathways are involved in the production of S-Adenosylmethionine, the universal methyl donor.

Background: Although combinations of biologically relevant polymorphic variants affect folate status, most studies have focused on the effects of indi

Background: Folate, choline, and betaine participate in homocysteine metabolism. It is not known whether they interact during pregnancy.Objective: Th