Maternal Vitamin B12 Levels During Pregnancy and Their Effects on Maternal Neurocognitive Symptoms: A Systematic Review

OBJECTIVE: Vitamin B₁₂ deficiency has been linked to neurocognitive symptoms. Vitamin B₁₂ deficiency in pregnancy may be associated with antenatal or postpartum depression along with other neurocognitive symptoms including restless leg syndrome. The objective of this study was to systematically review the literature regarding vitamin B₁₂ deficiency and insufficiency in pregnancy and its effects on maternal neurocognitive symptoms. DATA SOURCES: MEDLINE, Embase, and SCOPUS were searched from inception to October, 2020. STUDY SELECTION: Observational studies and randomized controlled trials of singleton pregnancies involving vitamin B₁₂ deficiency and reporting maternal neurocognitive outcomes were identified. DATA EXTRACTION AND SYNTHESIS: Data were synthesized and are presented narratively. CONCLUSIONS: The 5 studies included in the analysis did not demonstrate a statistically significant link between vitamin B₁₂ deficiency or insufficiency and either restless leg syndrome or depression in pregnancy. To date, evidence is lacking that would support a causal link between suboptimal vitamin B₁₂ serum levels and maternal restless leg syndrome or depression.