B12 during pregnancy
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The Importance of Vitamin B12 During Pregnancy
Prevalence of Vitamin B12 Deficiency in Pregnancy
Vitamin B12 deficiency is a common issue among pregnant women, particularly in regions like India, where 40-70% of pregnant women are affected1. This deficiency is linked to various adverse outcomes for both the mother and the child.
Impact on Pregnancy Outcomes
Neural Tube Defects and Birth Weight
Low maternal vitamin B12 levels are associated with a higher risk of neural tube defects (NTDs) and low birth weight in newborns1 2. Studies have shown that B12 deficiency increases the risk of low birth weight (birth weight <2,500 g) and preterm birth (gestation <37 weeks)2.
Gestational Diabetes and Pregnancy Complications
There is moderate-quality evidence suggesting that low B12 levels during pregnancy are linked to a higher risk of gestational diabetes and other complications such as recurrent pregnancy losses and pre-eclampsia1 7.
Long-term Health Outcomes for Offspring
Maternal B12 deficiency has been associated with adverse long-term health outcomes in offspring, including cognitive impairments, increased adiposity, and insulin resistance1 9.
Benefits of Vitamin B12 Supplementation
Maternal and Infant Health
Supplementation with vitamin B12 during pregnancy has shown to improve maternal and infant B12 status significantly. In a study conducted in Bangladesh, daily supplementation of 250 µg of B12 during pregnancy and postpartum improved B12 levels in mothers, infants, and breast milk4. This supplementation also reduced inflammatory responses in infants and improved vaccine-specific immune responses in mothers4.
Neurocognitive Development
Randomized controlled trials (RCTs) have indicated that B12 supplementation during pregnancy can have beneficial effects on the neurocognitive development of offspring, although its impact on birth weight remains inconclusive1.
Diagnostic and Predictive Biomarkers
Combined Indicator of Vitamin B12 Status (cB12)
Research has suggested pregnancy-specific reference ranges for various B12 biomarkers, including serum B12, holotranscobalamin (HoloTC), and methylmalonic acid (MMA). These biomarkers change significantly across trimesters, with cB12 values declining notably in the third trimester3. However, these biomarkers have limited predictive value for identifying mothers at risk of B12 deficiency later in pregnancy3.
Policy Implications
Given the high prevalence of B12 deficiency and its significant impact on pregnancy and offspring health, there is strong evidence to support the inclusion of vitamin B12 in existing nutritional programs, especially in regions with high deficiency rates like India1. This could extend the benefits of current programs aimed at preventing anemia to also address broader maternal and child health outcomes.
Conclusion
Vitamin B12 plays a crucial role in ensuring healthy pregnancy outcomes and long-term health for offspring. Addressing B12 deficiency through supplementation and policy changes can significantly improve maternal and child health, particularly in regions with high prevalence rates. Further research and large-scale studies are needed to strengthen the current evidence and optimize supplementation strategies.
Sources and full results
Most relevant research papers on this topic
Maternal Vitamin B12 Status During Pregnancy and Its Association With Outcomes of Pregnancy and Health of the Offspring: A Systematic Review and Implications for Policy in India
Low maternal vitamin B12 status in India is associated with increased risks of neural tube defects, low birth weight, and adverse offspring health outcomes.
Systematic Review
Highly CitedAssociations of Maternal Vitamin B12 Concentration in Pregnancy With the Risks of Preterm Birth and Low Birth Weight: A Systematic Review and Meta-Analysis of Individual Participant Data
Maternal vitamin B12 deficiency is associated with a higher risk of low birth weight and preterm birth in newborns.
Meta-Analysis
Very Rigorous JournalHighly CitedEvaluating the Diagnostic Value of a Combined Indicator of Vitamin B12 Status (cB12) Throughout Pregnancy
Trimester-specific reference ranges for vitamin B12 biomarkers in normal pregnancy are suggested, but these biomarkers have limited predictive value in identifying mothers at elevated risk of vitamin B12 insufficiency/deficiency during pregnancy.
RCTVitamin B12 supplementation during pregnancy and postpartum improves B12 status of both mothers and infants but vaccine response in mothers only: a randomized clinical trial in Bangladesh
Vitamin B12 supplementation during pregnancy and lactation improves maternal, infant, and breast milk B12 status, but only improves H1N1 vaccine-specific responses in mothers.
RCT
Rigorous JournalHighly CitedVitamin B12 status in pregnant women and their infants in South India
Impaired maternal vitamin B12 status during pregnancy is the single best predictor of infant vitamin B12 deficiency, even after adjusting for supplementation.
RCTInterventions with vitamins B6, B12 and C in pregnancy.
Vitamin C supplementation during pregnancy is not justified, while vitamin B6 supplementation may improve birthweight and reduce neural tube defects in offspring, but more research is needed.
Meta-AnalysisHighly CitedVitamin D3 and B12 Supplementation in Pregnancy.
Oral vitamin D3 and B12 supplementation during pregnancy failed to correct nutritional deficiencies in Bangladeshi pregnant women, while dietary supplementation and high dose vitamin D effectively corrected severe deficiency.
RCTVitamin B12 and Folate Levels During Pregnancy and Risk of Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis
The association between vitamin B12 and folate levels during pregnancy and the risk of gestational diabetes mellitus is unclear, with limited studies suggesting increased risk with higher RBC folate levels but majority studies found no association between serum folate and risk of GDM.
Meta-AnalysisLow Vitamin B12 in Pregnancy Is Associated With Adipose‐Derived Circulating miRs Targeting PPAR&ggr; and Insulin Resistance
Low vitamin B12 levels in pregnancy alter adipocyte-derived circulating microRNAs, potentially leading to an adipogenic and insulin resistance phenotype, leading to obesity.
In Vitro StudyRigorous JournalMaternal folic acid and vitamin B12 supplementation during medium to late gestation promotes fetal development via improving placental antioxidant capacity, angiogenesis and amino acid transport.
Maternal folic acid and vitamin B12 supplementation during medium to late gestation improves fetal development by reducing homocysteine levels in umbilical cord blood and promoting placental antioxidant capacity and vascular density.
RCT