Administration of either an iodinated or a gadolinium-based contrast media occasionally is indicated for an imaging study on a woman who is breast-feeding. Both the patient and the patient’s physician may have concerns regarding potential toxicity to the infant from contrast media that is excreted into the breast milk.
The literature on the excretion into breast milk of iodinated and gadolinium-based contrast media and gastrointestinal absorption of these agents from breast milk is very limited; however, several studies have shown that
1. less than 1% of the administered maternal dose of contrast medium is excreted into breast milk
2. less than 1% of the contrast medium in breast milk ingested by an infant is absorbed from the gastrointestinal tract.
Therefore, the expected dose of contrast medium absorbed by an infant from ingested breast milk is extremely low.
Iodinated X-ray Contrast Media (Ionic and Nonionic)
The plasma half-life of intravenously administered iodinated contrast medium is approximately two hours, with nearly 100% of the media cleared from the bloodstream within 24 hours. Because of its low lipid solubility, less than 1% of the administered maternal dose of iodinated contrast medium is excreted into the breast milk in the first 24 h ours. Because less than 1% of the contrast medium ingested by the infant is absorbed from its gastrointestinal tract, the expected dose absorbed by the infant from the breast milk is less than 0.01% of the intravascular dose given to the mother. This amount represents less than 1% of the recommended dose for an infant undergoing an imaging study, which is 2 mL/kg. The potential risks to the infant include direct toxicity and allergic sensitization or reaction, which are theoretical concerns but have not been reported.
Recommendation: Mothers who are breast-feeding should be given the opportunity to make an informed decision as to whether to continue or temporarily abstain from breast-feeding after receiving intravascularly administered iodinated contrast media. Because of the very small percentage of iodinated contrast medium that is excreted into breast milk and absorbed by the infant’s gut, we believe that the available data suggest that it is safe for the mother and infant to continue breast-feeding after receiving such an agent. If the mother remains concerned about any potential ill effects to the infant, she may abstain from breast-feeding for 24 hours with active expression and discard of breast milk from both breasts during that period. In anticipation to this, she may wish to use a breast pump to obtain milk before the contrast study to feed the infant during the 24 hour period following the examination.