If I am breastfeeding and need to have a medical test that requires the use of radiocontrast material, can I continue to breastfeed? Do I have to pump and discard my milk? If so, for how long—hours, days, weeks?

First the facts
According to the American College of Radiology (ACR), only a small amount (less than 1 percent) of the contrast material given to a breastfeeding women gets into her milk, and only a small amount (less than 1 percent) of the contrast material in the milk is absorbed by the baby from his or her gastrointestinal tract. Because breastfed babies are exposed to only a miniscule amount of radiocontrast material, there is no need to stop breastfeeding, even for a brief period of time.

Next the fallacy
Despite the ACR recommendations, women are often told to stop breastfeeding for 24 to 48 hours. Why? Perhaps old habits die hard. Perhaps health care providers fail to keep abreast of new scientific evidence. Perhaps the risks associated with the use of infant formula are poorly understood in a culture where bottle-feeding is considered normal.

Why are radiocontrast materials used?
While bones show up clearly on x-ray images, soft tissues and internal organs are often hard to see, so radiologists and imaging technologists may use radiocontrast materials to highlight specific body parts. Contrast agents are used with all kinds of imaging procedures including magnetic resonance imaging (MRI), x-ray exams, and computed tomography (CT) scans. They are administered intravenously (IV) or given as a drink or enema.

Contrast agents usually contain barium, iodine, or gadolinium. Barium sulfate is the most commonly used agent. Barium blocks the passage of x-rays so barium-filled organs stand out better on x-ray exams. For an exam of the upper gastrointestinal tract (esophagus or stomach), patients are asked to drink a mixture of barium sulfate and water. Vanilla or fruit flavoring is added to make the mixture taste better, albeit, not much! For an examination of the lower gastrointestinal tract (rectum or colon), a barium enema is given. Agents containing iodine are used to visualize the gallbladder, urinary tract, blood vessels, spleen, liver, and bile duct. Iodine contrast agents are clear liquids that are usually given through a tube placed in a vein (IV). Gadolinium-based agents are used for MRI scans.

Consider the benefits and the risks
Human milk is the ideal food for human babies. It contains more than 200 active ingredients and protects against a wide range of illnesses. When foods other than human milk are given to babies, especially those less than 6 months of age, the risk of acute and chronic disease increases significantly.

Currently, there is no evidence to show that use of contrast materials puts breastfeeding babies at risk. At the same time, there is compelling evidence to show that use of infant formula, even in small amounts, can have adverse effects, both short- and long-term.

So keep the breastmilk flowing.