Low maternal vitamin B12 is a risk factor for neural tube defects: a meta-analysis

Abstract

Objective. The objective of this study was to assess whether low level of maternal vitamin B12 is associated with an increased risk of fetal neural tube defects (NTDs), in order to contribute to research on further reduction of NTDs under a background of mandatory folic acid (FA) fortification.Methods. A meta-analysis was conducted. We retrieved and evaluated the studies published on the risk of low level of maternal vitamin B12 for NTDs. The homogeneity of the studies was examined using the forest graph. Meta-analysis was applied to calculate the odds ratio (OR) of fetal NTDs in relation to low maternal B12 and its 95% confidence interval (CI).Results. We identified nine published articles including 567cases and 1566 controls in the meta-analysis. All the studies selected were homogeneous according to the forest graph (χ2 = 15.05, P < 0.1). The estimated OR value of fetal NTDs in relation to low maternal B12 was 2.41 (95% CI: 1.90–3.06).Conclusion. Low maternal B12 status could be an important risk factor for the development of fetal NTDs. The addition of synthetic B12 to current recommendations for periconceptional FA tablet supplements or FA-fortified foods should be considered.