Can I take cyanocobalamin while pregnant or breastfeeding?

Pregnancy Adequate and well-controlled studies have not been done in pregnant women. However, vitamin B 12 is an essential vitamin and requirements are increased during pregnancy. Amounts of vitamin B 12 that are recommended by the Food and Nutrition Board, National Academy of Science-National Research Council for pregnant women (4 mcg daily) should be consumed during pregnancy.

Prescribing label, section “Pregnancy”: Cyanocobalamin (intramuscular, subcutaneous), Plano Pharmaceuticals Inc. Label on DailyMed. Quoted verbatim; US labels are written for US prescribers and patients.

This quote is from the intramuscular/subcutaneous formulation label.

Vitamin B12 is a normal component of human milk.[1] The recommended daily intake in lactating women is 2.8 mcg and for infants aged 6 months or less is 0.4 mcg.[2] Some authorities recommend 5.5 mcg per day during lactation.[3] Supplementation may be necessary to achieve these recommended daily intakes or to correct a known deficiency. Low doses (1 to 10 mcg) of vitamin B12 found in B complex or prenatal vitamins increase milk levels only slightly. Higher daily doses of 50 to 250 mcg are needed in cases of maternal deficiency. The breastfed infant is not exposed to excessive vitamin B12 in such cases, and their vitamin B12 status should improve if it was previously inadequate.

Poor health outcomes in infants with vitamin B12 deficiency include anemia, abnormal skin and hair development, convulsions, weak muscle tone, failure to thrive, mental developmental delay, and potentially abnormal movements.[4-8] Well-recognized at risk groups are exclusively breastfed infants of mothers with B12 deficiency due to minimal or no dietary intake of animal products[9-21] or pernicious anemia caused by a maternal malabsorption of B12.[18,22] Infant vitamin B12 status can be improved through maternal B12 supplementation during pregnancy and lactation.[23-26] Deficient mothers who miss the opportunity to supplement during pregnancy should still be encouraged to supplement during early lactation since infant vitamin B12 status correlates with milk vitamin B12 levels in breastfed infants up to 6 months of age.[27-30] Although there are cases reported of exclusively breastfed infants with vitamin B12 deficiency having biochemical and clinical improvement through adequate maternal supplementation alone,[9] direct supplementation of the infant is recommended when such treatments are available.[31-33]

“Summary of Use during Lactation”, LactMed record “Vitamin B 12” (LM1437), quoted verbatim. Everything LactMed reports about Vitamin B 12 while breastfeeding.

Nursing Mothers Vitamin B 12 is known to be excreted in human milk. Amounts of vitamin B 12 that are recommended by the Food and Nutrition Board, National Academy of Science-National Research Council for lactating women (4 mcg daily) should be consumed during lactation.

Prescribing label, section “Nursing Mothers”: Cyanocobalamin (intramuscular, subcutaneous), Plano Pharmaceuticals Inc. Label on DailyMed. Quoted verbatim; US labels are written for US prescribers and patients.

This quote is from the intramuscular/subcutaneous formulation label.