Medical studies usually have nuanced conclusions, so putting the right "spin" on interpretation of the results is important. This study represents one of the few times I noticed that the lay press did a better job explaining the results than did the medical press.
Source: Ray JG, Vermeulen MJ, Bharatha A, et al. Association between MRI exposure during pregnancy and fetal and childhood outcomes. JAMA. 2016;316(9):952-961; doi:10.1001/jama.2016.12126 doi: 10.1001/jama.2016.12126. See AAP Grand Rounds commentary by Dr. Dan Doherty (subscription required).
First, this was a pretty big study: over 1.4 million births from a database over a 12-year period in Ontario, Canada; pretty impressive. Second, it was a retrospective cohort study, prone to all sorts of unaccounted-for variables, meaning that results can only show at best an association between risk factors and outcomes, rather than lending support to a cause and effect relationship.
When the smoke cleared, the data showed no association between noncontrast MRI in the first trimester and any of a number of bad neonatal outcomes: stillbirths, neonatal death within 28 days of birth, congenital anomalies, neoplasms, hearing loss, or visual loss. (Other studies had shown lack of association with noncontrast MRI in 2nd and 3rd trimesters.)
The bad, and important, news showed a positive association of gadolinium-enhanced MRI exposure at any time in pregnancy with rheumatologic, inflammatory, or skin infiltrative conditions and with stillbirths and neonatal deaths. (Note there is some literature to support biologic plausibility of gadolinium exposure with adverse fetal events.) I agree with the authors' conclusion: "Until further studies are done, these findings suggest that gadolinium contrast should be avoided during pregnancy." This highlights the fact that this is a retrospective cohort study, and future prospective studies might reverse this finding, but it's too serious a finding to simply ignore.
So what about the media here? Check out the New York Times story from 9/20/16. The headline puts a positive, non-panic inducing spin up front, but the first sentence warns of the possible gadolinium risk. The entire story is concise and to the point, conveying what pregnant women would want to know, I think. Contrast this with what Aunt Minnie said. The headline is a little too positive, implying that all MRIs are safe in the first trimester. Even worse, the bad news about gadolinium is buried in the 10th paragraph, I suspect too deep for many in the public to have kept reading to that point. Shame on Aunt Minnie.
By the way, if you're wondering why I even bother to mention my Aunt Minnie, rest assured that she is not my aunt (or yours), but rather refers to a term used by a radiologist in the 1940s: if something on a radiograph looks like your Aunt Minnie, then it is your Aunt Minnie. The radiologist (allegedly Dr. Ben Folson at the University of Cincinnati, but I can't confirm) was well known for looking at images of complex cases and making diagnoses quickly. He reportedly remarked that it was like when his Aunt Minnie would come to the door. He just knew it was Aunt Minnie and didn't bother going through a long description and differential diagnosis. The term "Aunt Minnie" has been used by some in the medical education universe to describe how expert clinicians reason (e.g. "illness scripts"), but I think in this one instance, Aunt Minnie failed us.