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.

Keywords:

• Neural tube defects
• low maternal vitamin B₁₂
• meta-analysis

Declaration of interest: The study was sponsored by ‘The effectiveness evaluation of hospital-based comprehensive birth defects intervention methods’ of the People’s Republic of China (Grant number: 2006BA105A01). The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.