Gadolinium Exposure Risk Highest in Early Pregnancy

Jennifer Garcia

August 20, 2019

Some women may be inadvertently exposed to gadolinium-based contrast agents (GBCAs) early in pregnancy, a study has found. The results highlight the need for effective pregnancy screening measures before conducting advanced imaging studies, the researchers say.

"Given the potential risks of gadolinium exposure during pregnancy, we sought to examine the characteristics of real-world use patterns in a large sample of pregnant women," write Steven Bird, PharmD, PhD, of the US Food and Drug Administration's (FDA's) Division of Epidemiology, and colleagues.

The study, published online August 20 in Radiology, evaluated information from 16 partners in the FDA's Sentinel System, a program that allows for active surveillance of data from various healthcare systems to monitor the safety of regulated medical products. The researchers collected data from 4,692,744 pregnancies resulting in live birth between 2006 and 2017. Within this cohort, the researchers identified those women who underwent outpatient MRI, with or without contrast; these patients were further categorized on the basis of gestational week at time of MRI.

Among the more than 4.6 million pregnancies evaluated, there were 6879 exposures to GBCAs. These exposures occurred in 5457 pregnancies, representing one per 860 pregnancies (0.12% of all pregnancies). Exposures occurred primarily during the first trimester (70.2%), a 4.3-fold greater prevalence than in the second trimester and a 5.1-fold greater prevalence than in the third trimester. The authors note that these results suggest exposure to GBCAs may often occur before pregnancy is even recognized.

"The high prevalence of unplanned pregnancies in the United States may contribute to failures to recognize early pregnancy among women who underwent MRI," note Bird and colleagues.

Gadolinium can cross the placenta and enter the fetal circulation; however, fetal effects of exposure are still unclear. Use of GBCAs is not recommended during pregnancy, and guidelines from the American College of Radiology recommend that women of reproductive age undergo screening for pregnancy prior to being evaluated with MRI.

The researchers also recommend other approaches to avoid inadvertent exposure, including "use of a safety screening form asking about potential for pregnancy, direct questioning by radiology technologists regarding pregnancy, prominently displayed signs asking women to notify radiology staff if they might be pregnant, and pregnancy testing, when appropriate."

Funding for the study was provided by the FDA. The authors report no relevant financial relationships.

Radiology. Published online August 20, 2019. Full text

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