Epidemiologists have flagged concern over women unwittingly being exposed to gadolinium-based contrast agents for MRI when they don’t realise they’re pregnant.

A US Food and Drug Administration (FDA) researcher says the safety of these contrast agents has not been established and their use in pregnancy is not recommended unless it’s essential to the health of the woman or fetus.

“It is known that gadolinium contrast crosses the placenta and enters fetal circulation,” says Dr Steven Bird (PhD) from the FDA’s Center for Drug Evaluation and Research.

“Available data from cohort studies and case reports have revealed inconsistent findings regarding the association between [these agents] and adverse fetal outcomes.”