An MRI during pregnancy is considered safe for both you and your baby. Unlike X-rays or CT scans, MRI uses magnetic fields and radio waves rather than radiation, and both the American College of Obstetricians and Gynecologists (ACOG) and the American College of Radiology list it alongside ultrasound as a preferred imaging option for pregnant patients. That said, the scan is typically reserved for situations where it’s genuinely needed to answer a clinical question, and one component of MRI, a contrast dye called gadolinium, does carry specific risks worth understanding.
No Evidence of Harm From the Scan Itself
There are three theoretical concerns about MRI during pregnancy: the possibility of birth defects, tissue heating, and noise-related damage to the baby’s hearing. None of these have been confirmed in human studies. The magnetic field does not produce the kind of energy that damages DNA, so it doesn’t carry the same risks as radiation-based imaging. Tissue heating from the scanner is proportional to how close the tissue is to the machine’s coils, making it negligible near the uterus. And studies tracking babies exposed to MRI in utero have found no increase in hearing problems at birth.
One large study compared hearing screening results from 751 newborns who had been exposed to MRI before birth with over 10,000 unexposed newborns. The rate of hearing impairment at birth was actually 0% in the exposed group, compared to 0.34% in the unexposed group. Birth weight and health scores at delivery also showed no differences regardless of which trimester the scan was performed, how many scans occurred during the pregnancy, or what type of MRI protocol was used.
First Trimester Safety
You might assume the first trimester is the riskiest time for any medical procedure, since that’s when organs are forming. But the American College of Radiology has concluded that no special consideration is needed for first-trimester MRI compared to any other point in pregnancy. A study tracking over 1,700 pregnancies with first-trimester MRI exposure found no statistically significant increase in stillbirth, congenital anomalies, cancer, or hearing loss when compared to more than 1.4 million unexposed pregnancies.
One narrower finding deserves mention: when researchers looked specifically at MRI exposure between weeks 5 and 10 of pregnancy, they observed a higher rate of vision problems in children followed to age 4, with roughly double the risk compared to unexposed children. This was a single finding from one dataset, and it hasn’t been replicated, but it’s part of why clinicians still prefer to use MRI only when there’s a clear medical reason rather than as a routine screening tool.
The Real Risk: Gadolinium Contrast Dye
The bigger concern isn’t the MRI itself but gadolinium, the contrast agent sometimes injected into a vein to make certain tissues show up more clearly on the scan. Not every MRI requires contrast, but when it’s used during pregnancy, gadolinium crosses the placenta and enters the amniotic fluid. The baby swallows that fluid, the gadolinium passes through the baby’s kidneys back into the amniotic fluid, and the cycle repeats. The longer it lingers, the more it can break apart from its protective chemical shell, potentially releasing free gadolinium into the baby’s environment.
A study of 397 pregnancies with gadolinium exposure found a 36% higher risk of the child developing inflammatory or rheumatologic skin conditions compared to unexposed pregnancies. There was also a small increased risk of stillbirth or neonatal death, though the numbers were small. No cases of a severe kidney-related scarring condition called nephrogenic systemic fibrosis have been documented in a newborn after in-utero exposure, but the theoretical risk exists because the baby’s kidneys are immature.
Because of these findings, guidelines are clear: gadolinium should only be used during pregnancy if skipping it would meaningfully reduce the scan’s diagnostic value and if the information is expected to improve outcomes for the mother or baby. In practice, many MRI scans ordered during pregnancy are done without contrast.
Why Your Doctor Might Order an MRI
Ultrasound is always the first choice for imaging during pregnancy because it’s inexpensive, portable, and thoroughly studied. But ultrasound has limits. MRI provides far more detail for soft tissue, making it useful when doctors need to evaluate conditions that ultrasound can’t fully characterize. Common reasons include suspected appendicitis, abnormal placental attachment, complex fetal brain abnormalities that ultrasound picked up but couldn’t fully define, and maternal tumors or neurological symptoms that need investigation.
In these situations, delaying the scan until after delivery could mean missing a diagnosis that puts the pregnancy at risk. The benefit of getting an accurate answer typically outweighs the theoretical concerns of the scan.
What the Scan Feels Like
The MRI experience during pregnancy is the same as it would be otherwise: you lie on a narrow table that slides into a tube-shaped scanner, and the machine produces loud knocking and buzzing sounds for 20 to 60 minutes depending on what’s being imaged. You’ll wear ear protection, and the baby is somewhat insulated from the noise by amniotic fluid and your body tissues.
Later in pregnancy, lying flat on your back can cause dizziness or a drop in blood pressure because the weight of the uterus compresses a major vein. If you’re far enough along for this to be an issue, the technologist will typically place a wedge or cushion under one hip to tilt you slightly to the left, which takes the pressure off and keeps blood flowing normally. You can also let the team know at any time if you feel lightheaded or uncomfortable.
Breastfeeding After a Contrast MRI
If you’ve already delivered and need a contrast MRI while breastfeeding, there’s good news: you do not need to pump and dump. Only a tiny fraction of gadolinium makes it into breast milk, and even less is absorbed through the baby’s gut. Both the American Academy of Pediatrics and the American College of Radiology consider all commonly used gadolinium contrast agents compatible with continued breastfeeding. You can nurse immediately after your scan without interruption.