Is MRI contrast safe while breastfeeding?

What does the evidence say about MRI contrast while breastfeeding?

1. ACOG states that breastfeeding should not be interrupted after gadolinium administration. This guidance applies to gadolinium used for MRI and does not depend on routinely pumping and discarding milk. 1
2. In a pharmacokinetic study of 20 lactating women, less than 0.04% of the maternal intravenous gadopentetate dose was excreted into milk over 24 hours. The study measured milk excretion, not infant blood levels or clinical outcomes. 2
3. LactMed reports that gadopentetate levels in milk are low and oral absorption by the infant is poor. North American professional guidance does not require nursing interruption, although gadopentetate itself is no longer marketed in the United States. 3
4. LactMed describes gadobutrol as one of the more stable gadolinium agents and says professional guidance does not require nursing interruption. Direct published experience during breastfeeding is limited, so an alternate agent may be preferred for a newborn or preterm infant when feasible. 4
5. Radiopharmaceuticals are a different exposure category from MRI gadolinium. A review of 53 lactating patients receiving 16 radiopharmaceuticals found that milk excretion varied by compound, with recommendations ranging from no interruption to temporary interruption or, for iodine-131, cessation. 5

How MRI contrast changes by nursing stage

• Early weeks. In the early weeks, tell radiology if the infant was born preterm or has kidney concerns. Professional guidance still supports nursing after gadolinium, but LactMed notes that a more studied agent may be preferred for a newborn or preterm infant when choices are clinically equivalent.
• Established nursing. With established nursing, routine interruption after an extracellular gadolinium contrast agent is not recommended. Feeding just before the scan may simplify logistics, but it is not required to reduce exposure.
• Weaning. During weaning, the same guidance applies: gadolinium exposure through milk is very low and a contrast MRI does not create a medical need to accelerate weaning. Ask separately about any nuclear-medicine tracer because interruption periods depend on the radiopharmaceutical.