Exposure to common MRI contrast agent during pregnancy is worrisome or not, study explains

USA: Gadolinium exposure in utero by the passage of gadolinium-based contrast agents (GBCAs) through the placenta during pregnancy has been linked to increased risk for stillbirth, neonatal death, and skin conditions in the newborn. Now, a recent study has found that a concerning although a small number of women are being exposed to the magnetic resonance imaging (MRI) contrast agent often early in the pregnancy.

"This study identified higher rates of GBCA exposure during the first few weeks of pregnancy compared with the later weeks of pregnancy, suggesting inadvertent exposure to GBCAs might occur before pregnancy is recognized," the authors report in the Radiology journal.

MRI is used for noninvasive high-resolution imaging of internal organs, bone, blood vessels, and soft tissues. The use of GBCAs with MRI provides additional information and is now being used in 30-45% of the magnetic resonance imaging examinations in the US. In GBCAs the otherwise toxic unbound gadolinium molecules are tightly bound to a ligand providing protection against toxicity. Recent research suggests that trace levels of the dye may remain in the body after the MRI, but whether this poses risks remains unclear.

For the purpose, they used data from the Sentinel Distributed Database to identify U.S. pregnancies that resulted in live births (2006 and 2017) from 16 data contributors. They then evaluated the prevalence of magnetic resonance imaging procedures with and without a gadolinium-based contrast agent (GBCA) among pregnant and matched nonpregnant women for anatomic location and trimester.

Key findings include:

• Of the nearly 4.7 million pregnancies, there were 6,879 exposures to GBCAs in 5,457 pregnancies (0.12 per cent of all pregnancies), or one contrast-enhanced magnetic resonance imaging examination per 860 pregnancies.


• Roughly half of contrast-enhanced MRI examinations were performed in the head (3,499 procedures), although pelvic and abdominal magnetic resonance imagingcomprised 22.3 per cent of all contrast-enhanced magnetic resonance imagingexaminations during pregnancy.


• The majority (70.2 per cent) of GBCA exposures occurred during the first trimester, which was a 4.3-times greater number than in the second trimester and a 5.1-times greater number versus the third trimester.

The research team pointed to several ways imaging centers could prevent inadvertent gadolinium exposure in pregnant women.

Those include using a written form or directly asking women if they could be pregnant, prominently displaying signs telling women to notify staff if they might be pregnant, and pregnancy testing when appropriate.