(Reuters Health) – Women who are not aware that they are pregnant when undergoing magnetic resonance imaging (MRI) may be exposed to a chemical that may not be safe for the fetus, warns a new report.
The chemical, a dye called gadolinium contrast, is used in about 30 to 45 percent of MRI studies in the US to improve the differences between internal organs, soft tissues, blood vessels, and bones.
"Gadolinium contrast is known to cross the placenta and enter the fetal circulation," said senior study author Steven Bird of the Food and Drug Administration's Center for Drug Assessment and Research Silver Spring, Maryland.
The safety of gadolinium contrast agents (GBCAs) in pregnant women "has not been established and their use during pregnancy is only recommended if essential for the health of the woman or the fetus," Bird Reuters Health Mail with. "Available data from cohort studies and case reports have resulted in inconsistent findings regarding the association between GBCAs and adverse fetal outcomes."
Bird and colleagues used the FDA-funded Sentinel Distributed Database to analyze data from nearly 4.7 million pregnancies between 2006 and 2017. They examined the prevalence of MRI interventions with and without GBCA in pregnant women, including of the trimester and the location of the scan on the body.
The research team found 6,879 GBCA exposures in 5,457 pregnancies, equivalent to GBCA testing per 860 pregnancies or about 0.1 percent of all pregnancies. Half of the MRI was scans of the head, but 22% were pelvic and abdominal scans, possibly affecting the fetus.
About 70 percent of exposures in pregnant women occurred in the first trimester, the authors of the study wrote in the journal Radiology.
The finding that most pregnancies with gadolinium exposure in the uterus occurred in the first few weeks "when a woman may not have been aware of her pregnancy."
"Increased attention to pregnancy screening may be Bird, said, "Healthcare providers should only use GBCAs if the additional diagnostic information is needed, in contrast."
Bird and colleagues are working on and funding a follow-up study of pregnant women, To evaluate the fetal and neonatal outcomes after exposure to GBCA during pregnancy, the FDA will continue to monitor reports of adverse events, he said.
The American College of Radiology recommends that women of childbearing age be screened before any MRI scan To investigate pregnancy and states That GBCAs should only be used after careful consideration of the benefits Mother and the fetus outweigh the potential risks.
"Magnetic resonance imaging is increasingly using gadolinium-based contrast agents," said Javier Lafuente of Gregorio Maranon Hospital in Madrid, Spain. Lafuente, who was not involved in this study, examined GBCAs in MRI.
"Generally these compounds are safe," he said. Nonetheless, "side effects, the potential for nephrotoxicity of these compounds, and the potential for nephrogenic systemic fibrosis development, even in non-pregnant patients, may have contraindications to their clinical application."
/bit.ly/2KIp6C2 Radiology, online August 20, 2019.