Serum Total Vitamin B12 or Active Vitamin B12: Which is a Better Marker for Vitamin B12 Deficiency during Pregnancy? A Retrospective Cohort Study from South India

Résumé fourni par la source

Background: Serum Vitamin B12 level is routinely analyzed using total Vitamin B12 assay. It can also be analyzed by active B12 assay. In this study, we compared the association of total and active Vitamin B12 levels with maternal medical complications associated with Vitamin B12 in pregnancy. Materials and Methods: Blood sera of 217 pregnant women in their first trimester were included to conduct this retrospective study. The levels of active B12 and total B12 were analyzed by Roche cobas e 801. The distribution of active and total B12 among the anemic groups was analyzed using the Mann–Whitney U -test. Categorical associations of complications with active and total B12 were done using Chi-square statistics. The discriminating ability of active and total B12 was analyzed by the receiver operating characteristic (ROC) curve. Results: The hemoglobin levels and the maternal medical complications associated with Vitamin B12, in the total and active Vitamin B12-deficient groups were found to be similar when compared to the corresponding nondeficient groups. There is a positive correlation between total and active Vitamin B12 assay ( r = 0.52, P < 0.01). The predictive ability of total and active B12 for both neonatal and maternal outcomes assessed using the ROC curve reported an AUC <0.70. Conclusions: Total B12 assay was strongly positively correlated with active B12 assay. However, neither of these predicted maternal medical complications or neonatal complications associated with B12 deficiency. Therefore, we suggest a continuation of the standard practice of total Vitamin B12 assay over active B12 assay for the estimation of B12 deficiency in pregnancy especially in low- and middle-income countries like India.

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