The prescribing information for cyanocobalamin injection states that adequate and well-controlled studies have not been done in pregnant women. It also names recommended amounts for pregnancy, lactation and childhood. A Cochrane review of oral supplementation in pregnancy states that the potential impact on longer-term clinical and functional maternal and child health outcomes has not yet been established. This guide reports these statements and does not judge them.
What the label says
These statements come from the prescribing information for cyanocobalamin injection. The nursing and children statements appear under its nursing mothers and pediatric use headings.
| Question | What the source says |
|---|---|
| Pregnancy: what does it say about studies? | The label states that adequate and well-controlled studies have not been done in pregnant women, and that vitamin B12 is an essential vitamin and requirements are increased during pregnancy. |
| Pregnancy: what amount does it name? | The label states that the amounts 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. |
| Nursing mothers: what does it say? | The label states that vitamin B12 is known to be excreted in human milk, and that the recommended amount for lactating women (4 mcg daily) should be consumed during lactation. |
| Children: what does it say? | The label states that intake in children should be in the amount (0.5 to 3 mcg daily) recommended by the Food and Nutrition Board, National Academy of Science-National Research Council. |
The label ties each amount to the board's recommendation. The sentences cited do not state an injection dose, and they do not describe any effect of B12 in milk on a nursing infant.
What the label's patient section and the NHLBI say
The same label has an information for patients section. It states that the need for vitamin B12 is increased by pregnancy and lactation, and that deficiency has been recognized in infants of vegetarian mothers who were breast fed, even though the mothers had no symptoms of deficiency at the time.
The NHLBI, in a patient page on vitamin B12-deficiency anemia, states that the recommended daily amounts of vitamin B12 depend on your age, your sex, and whether you are pregnant or breastfeeding, and that your healthcare provider can look at your medical history to help determine how much vitamin B12 you need each day.
These sentences do not state an injection dose, and they do not say what an injection does in pregnancy or lactation.
What a Cochrane review of oral supplementation found
A Cochrane review of trials of oral vitamin B12 supplementation during pregnancy states that supplementation may improve maternal and infant vitamin B12 status. It adds that the potential impact on longer-term clinical and functional maternal and child health outcomes has not yet been established.
Two limits apply. The review concerns oral supplementation, not injection. The sentence cited also does not state a dose, a length of treatment, or whether participants had a deficiency, so it should not be carried over to people with or without one.
What this does not tell you
These sources give no verdict on B12 injections in pregnancy, breastfeeding or childhood. The label says adequate and well-controlled studies have not been done in pregnant women, and the Cochrane review says longer-term outcomes have not yet been established for oral supplementation. The 4 mcg and 0.5 to 3 mcg amounts are the label's reference to a board's recommendations, not a dose for any person. Decisions about treatment during pregnancy, breastfeeding or childhood belong to a licensed provider.