Functional significance of low serum vitamin B12 levels in pregnancy

Abstract

The physiological significance of low levels of vitamin B12 in serum in late pregnancy was assessed by a functional test viz. urinary excretion of methylmalonic acid (MMA) after a valine load. This was normal in all but one subject despite low levels of vitamin B12 in serum in many of these subjects. Assay of serum vitamin B12 levels in pregnant women and control subjects by two different techniques viz. radio isotope dilution and microbiological methods gave essentially similar results for both groups, although the absolute values in both the groups were over-estimated by the former technique. The data presented indicate that there is no evidence of functional inadequacy in pregnant women with low levels of vitamin B12 in serum.