Is Cyanocobalamin Co 57 safe while breastfeeding?
Here is what LactMed, the Drugs and Lactation Database published by the U.S. National Institute of Child Health and Human Development (NICHD), reports about Cyanocobalamin Co 57. The text below is quoted from that source — it is not our own verdict.
Summary of use during breastfeeding
Information in this record refers to the use of cyanocobalamin Co 57 as a diagnostic agent. Limited data indicate that excretion of radioactivity into breastmilk following cyanocobalamin Co 57 is low and does not require withholding of breastfeeding after diagnostic use. However, to minimize the radiation dose to the infant, some authors suggest that previously saved milk could be substituted for one feeding at about 24 hours after the dose.[1]
Mothers concerned about the level of radioactivity in their milk could ask to have it tested at a nuclear medicine facility at their hospital. When the radioactivity is at a safe level, she may resume breastfeeding. A method for measuring milk radioactivity and determining the time when a mother can safely resume breastfeeding has been published.[2]
Effects on the breastfed infant
Relevant published information was not found as of the revision date.
Effects on milk supply
Relevant published information was not found as of the revision date.
Levels in milk
Co 57 decays by electron capture with a physical half-life of 271.79 days.
Maternal Levels. A woman who was 3 weeks postpartum was given oral cyanocobalamin Co 57 in a dose of 18.6 kBq, followed by an intravenous dose of unlabeled cyanocobalamin as part of the Schilling test. Milk samples were collected 6 times during the first 25 hours, then at 49 and 73 hours after the dose. Peak milk radioactivity occurred between 17 and 25 hours, with levels of 0.25 to 0.26 Bq/mL. The woman was found to have some cyanocobalamin malabsorption, so the milk levels may have been lower than in a mother with unimpaired absorption.[1]
Infant Levels. Relevant published information was not found as of the revision date.
“No published information” means the studies do not exist yet — not that Cyanocobalamin Co 57 is known to be harmful, and not that it is known to be safe. Your prescriber or pharmacist can weigh your baby's age and whether a better-studied alternative would do the same job. Worth asking before stopping a medicine you need.
Source: Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Cyanocobalamin Co 57” (LM1109). LactMed on NCBI Bookshelf. LactMed is a registered trademark of the U.S. Department of Health and Human Services.
Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.