Murphy Michelle M, Molloy Anne M, Ueland Per M, Fernandez-Ballart Joan D, Schneede Jörn, Arija Victoria, Scott John M
Unitat de Medicina Preventiva i Salut Pública, IRCIS, Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Reus, 43201 Spain.
J Nutr. 2007 Aug;137(8):1863-7. doi: 10.1093/jn/137.8.1863.
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 (P(10), P(90))] were significantly reduced from preconception [cobalamin: 293 (155, 535) pmol/L; holoTC: 63 (38,98) pmol/L; MMA: 0.12 (0.09, 0.17) micromol/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) micromol/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) micromol/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: R(2) = 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.
孕期钴胺素状态受损可能使母亲和孩子在哺乳期及后续发育过程中面临缺乏的风险。我们调查了孕期钴胺素状态的变化是否与母亲和脐带中的状态受损有关。测定了92名女性在孕前、妊娠8周、20周、32周、分娩时及脐带中的血浆钴胺素、甲基丙二酸（MMA）和全转钴胺素（holoTC）浓度。所有变量[几何平均百分位数10、90（P(10)，P(90)）]从孕前[钴胺素：293（155，535）pmol/L；holoTC：63（38，98）pmol/L；MMA：0.12（0.09，0.17）μmol/L]到妊娠20周时[钴胺素：230（123，432）pmol/L；holoTC：48（34，78）pmol/L；MMA：0.11（0.08，0.15）μmol/L，P<0.001]均显著降低。在妊娠剩余时间[32周：198（107，339）；分娩时：224（117，444）；P<0.001]和[32周：45（26，82）；分娩时：40（23，79）；P<0.05]，血浆钴胺素和holoTC仍较低。到32周时，MMA高于孕前[0.14（0.09，0.20）μmol/L；P<0.01]。32周和分娩时的血浆holoTC与脐带MMA呈负相关（r=-0.51，P<0.001和r=-0.40，P<0.01）。孕前holoTC较低的女性在32周和分娩时MMA的升高幅度更大。仅在孕前holoTC较低的女性中，32周和分娩时的母亲MMA与脐带MMA显著且独立相关（回归模型：R(2)分别为0.707、0.682；P<0.01）。孕期钴胺素生物标志物MMA的适度升高可能表明细胞内钴胺素状态存在功能性耗竭。
