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Detailed medicine guidance

Pregnancy, breastfeeding and fertility while taking cyanocobalamin

NHS medicines information on cyanocobalamin and whether you can take it while pregnant or breastfeeding.

About this information

This NHS content is written for people in England. Medicine names, availability, prescribing and services may differ in other countries.

Cyanocobalamin and pregnancy

Cyanocobalamin is safe to take in pregnancy.

You do not usually need to take vitamin B12 supplements when you're pregnant or breastfeeding, unless your doctor has advised you to. You should be able to get all the vitamins you need if you eat meat, fish, eggs, milk and dairy foods.

Cyanocobalamin and breastfeeding

It's OK to take cyanocobalamin if you're breastfeeding.

Vitamin B12 (including cyanocobalamin) is a natural part of breast milk. Cyanocobalamin does pass into breast milk, but it's unlikely to cause any side effects in your baby.

If you notice that your baby is not feeding as well as usual, or if you have any other concerns about your baby, talk to your midwife, health visitor, doctor or pharmacist as soon as possible.

View the original NHS website page ↗. Refreshed 19 August 2026.

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