Some women are being exposed to gadolinium MRIs during the early stages of pregnancy, possibly before they even know they’re expecting.
While the actual number is small, the authors of a new study published in Radiology concluded that more must be done to avoid gadolinium exposure during the first trimester.
Gadolinium is a toxic heavy metal used in MRI contrast dyes to improve the appearance of images on a scan. These products are contraindicated in patients with impaired kidneys because of their association with a debilitating disorder called Nephrogenic Systemic Fibrosis. But until recently, it was thought that gadolinium MRIs posed no risk to individuals with normal renal function.
In December 2017, however, the U.S. Food & Drug Administration (FDA) warned that several studies had suggested gadolinium could be retained in the brain, tissues, and organs, for months or years after an MRI. While the agency has yet to concluded that gadolinium deposits pose any health risk, it did order manufacturers to note the potential for retention on their product labels. The FDA also directed the companies to conduct post-market studies of their gadolinium-based MRI agents in order to shed more light on their safety and effectiveness.
In its advice to health care providers, the agency recommended that doctors consider the retention potential of each agent when considering a gadolinium MRI for patients at highest risk of retention, including children, pregnant women, and those who’ve had multiple life-time doses.
The authors of the Radiology study found doctors rarely prescribe gadolinium MRIs for pregnant women. In fact, their analysis of 4.5 million live births that occurred in the United States from 2006 to 2017 identified gadolinium exposure in just 1 out of every 850. However, nearly ¾ of those exposures occurred during the first trimester of pregnancy, suggesting the subjects underwent gadolinium MRIs before they were even aware of the pregnancy.
“Unintended fetal exposures to gadolinium can occur during early pregnancy among women who are not yet aware they are pregnant. Increased attention to existing pregnancy screening measures may help reduce inadvertent exposures to gadolinium contrast,” said lead-author Steven Bird, Pharm.D., Ph.D., of the FDA’s Division of Epidemiology.
Dr. Bird and his colleagues suggested several ways to avoid inadvertent gadolinium exposure in pregnant women, including: