A nested case-control study to evaluate the association between fetal growth restriction and vitamin B12 deficiency

Abstract

Objectives: To study the association between maternal vitamin B12 levels and fetal growth restriction.

Methods: In this nested case-control study, a cohort of low-risk women attending the antenatal clinic had their blood samples taken and stored at 28-31 weeks gestation. They were followed until delivery. Fifty-eight women delivering babies less than 2500 g were taken as cases and an equal number of controls delivering babies more than 2500 g were taken from the same cohort. Their B12 levels were assayed and studied for statistical significance.

Results: The baseline characteristics of both groups were similar. The number of women with serum B12 levels less than 200 pg/mL were similar in both groups: 33% versus 29% (P = 0.84). Type of kitchen fuel used was taken as a surrogate marker for socioeconomic status. More women in the cases used non-LPG (liquid petroleum gas) kitchen fuels such as kerosene and wood than in controls, 35% versus 19% (P = 0.06).

Conclusions: No association between maternal vitamin B12 levels and fetal growth restriction was found in this study. Low birth weight babies were more common in women of low socioeconomic status.

Keywords: fetal growth restriction; nested case control; poor nutrition; socioeconomic status; vitamin B12.