Biochemical indices of vitamin B12 nutrition in pregnant patients with subnormal serum vitamin B12 levels

✍ Scribed by Dr. Jack Metz; Katherine McGrath; Michael Bennett; Keith Hyland; Teodoro Bottiglieri

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 494 KB
• Volume: 48
• Category: Article
• ISSN: 0361-8609
• DOI: 10.1002/ajh.2830480409

✦ Synopsis

To determine the significance of the commonly observed fall in serum vitamin B,, levels during pregnancy, serum levels of the BIZ metabolites methylmalonic acid (MMA) and homocysteine (Hcy) were measured in a group of 50 pregnant patients with subnormal serum BIZ (range 45-199 pglml) and the results compared with those of 25 pregnant controls (serum Blz2O8-580 pglml). Mean values for serum MMA and total Hcy in the subnormal B,, group were 445.4 nmollL and 7.03 pnol/L, respectively, which were not significantly different from the mean MMA of 440.5 nmollL and Hcy of 6.88 nmol/L in the controls. For the total group of patients, neither serum MMA nor serum Hcy levels correlated with serum B12 One-third of pregnant patients showed elevated serum MMA values, independent of BIZ status. Significant elevation of serum Hcy was detected in only two patients, both with subnormal serum BIZ and hematological evidence of BIZ deficiency. We conclude that the usual fall in serum BIZ concentration in pregnancy does not reflect BIZ deficiency at the biochemical level. In establishing true BIZ deficiency in pregnancy, the serum Hcy level (in the absence of folate deficiency) but not serum MMA, is of value.