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MRI may be safe in early pregnancy without use of gadolinium

Exposure to MRI during the first trimester of pregnancy did not increase the risk for harm to the fetus, according to findings published in JAMA.

However, gadolinium-enhanced MRI increased the risk for inflammatory and rheumatological conditions, as well as stillbirth and neonatal death, Joel G. Ray, MD, MSc, FRCPC, from St. Michael's Hospital in Toronto, and colleagues wrote.

"Current recommendations are to forgo use of gadolinium-enhanced MRI at any point during pregnancy, unless absolutely essential, and to carefully consider use of nonenhanced MRI in the first trimester," they wrote. "Clinicians need more data about the long-term safety for the child exposed to the MRI in the first trimester of pregnancy or to gadolinium at any time during pregnancy."

Ray and colleagues used universal health care databases to identify 1,424,105 deliveries in Ontario, Canada between 2003 and 2015. The rate of MRI was 3.97 per 1,000 pregnancies.

In comparing fetuses that were not exposed to MRI (n = 1,418,451) to those that were (n = 1,737) in the first trimester, researchers reported 9,844 stillbirths vs. 19, respectively (adjusted relative risk = 1.68; 95% CI, 0.97-2.9). In addition, there was not an increased risk for vision or hearing loss, neoplasm or congenital anomalies between these groups.

In comparing fetuses that were exposed to gadolinium MRI (n = 397) to those not, Ray and colleagues found increased rates of rheumatological, inflammatory or infiltrative skin conditions (adjusted HR = 1.36; 95% CI, 1.09-1.69). Stillbirths and neonatal deaths were also more likely in fetuses exposed to gadolinium MRI (adjusted RR = 3.7; 95% CI, 1.55-8.85).

"The current findings inform published recommendations about the safety of MRI in the first trimester of pregnancy," Ray and colleagues wrote. "Pregnancy is not a contraindication to MRI, which provides highly detailed images without the use of ionizing radiation. We did not evaluate the safety of MRI after the first trimester, as some nongadolinium MRIs are performed in the second or third trimester for a fetal indication, such as a fetal anomaly or tumor, heightening the chances of confounding by indication."

They continued: "Others suggest that MRI exposure in the second and third trimester appears to be safe in terms of normal vision and hearing in childhood. Following inadvertent or prior to intentional MRI exposure in the first trimester, a discussion about a potentially slightly higher risk of vision loss in the child should be balanced by an acknowledgement that it is not known to be associated with a higher risk of other adverse outcomes." – by Chelsea Frajerman Pardes

Disclosures: The researchers report no relevant financial disclosures.