The findings of a recently published Journal of the American Medical Association article have demonstrated that the MRI exposure during the first trimester of pregnancy was not associated with an increased risk of fetal and childhood anomalies.
With the increased rate of medical imaging during pregnancy, concern has been raised about the safety of these various modalities.
It is emphasized that during pregnancy, wherever possible, the safest imaging modality should be chosen. It’s generally accepted that Magnetic Resonance Imaging (MRI) and Ultrasonography are safe during the second and third trimester of pregnancy. The concerns are expressed about the safety of MRI during the first trimester.
The diagnostic accuracy of MRI can be improved with the intravenous usage of Gadolinium (a contrast media). Gadolinium is not advised during the first trimester of pregnancy due to its teratogenicity. Gadolinium can cross the placenta to the fetus and it can also be excreted by the fetus’s kidney to amniotic fluid in the second and third trimesters.
Keeping all of this in mind, clinicians need more information regarding the short term and long term safety of MRI in pregnancy especially in the first trimester.
In a recently published Journal of the American Medical Association article, scientists have evaluated the association between MRI exposure during pregnancy and fetal and childhood outcomes.
This retrospective cohort study included all maternal-child pairs in the province of Ontario, Canada, with the delivery of a live-born or stillborn child occurring between April 2003 and March 2015.
Two separate exposures were evaluated; the first cohort was comprised of all mothers with an MRI during the first trimester of pregnancy. The second cohort was comprised of mothers who had a Gadolinium-enhanced MRI during any trimester of the pregnancy. The outcomes for first cohort included stillbirth after 20 weeks’ gestation or neonatal death before 28 days after birth, any congenital anomaly excluding children with a concomitant chromosomal disorder, neoplasm, vision loss, and hearing loss.
In the second cohort (gadolinium) the outcome was defined as the occurrence of any of rheumatological, inflammatory or infiltrative disease.
The findings have shown that of the 1,424,105 deliveries, the overall rate of MRI exposure was 3.97 per 1000 pregnancies. There was no statistically significant difference in an adjusted relative for stillbirth and fetal and neonatal death between the offsprings of MRI-exposed and not-exposed mothers. The risk was also not significantly higher for congenital anomalies, neoplasm, or vision or hearing loss. Comparing gadolinium MRI (n = 397) with no MRI, there was a greater risk of rheumatological, inflammatory and infiltrative disease as well as stillbirth and deaths in the offsprings of mothers who were exposed to Gadolinium-enhanced MRI.
The researchers have concluded, exposure to MRI during the first trimester of pregnancy was not associated with increased risk of harm to the fetus or child in the early childhood. Gadolinium-enhanced MRI at any time during pregnancy was associated with an increased risk of rheumatological, inflammatory, or infiltrative skin conditions and risk of stillbirth or neonatal death.
Written By: Nima Makhdami, M.D.