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MRI Scan In Pregnancy: Safety, Risks, And Alternatives

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IN THIS ARTICLE

“Magnetic resonance imaging or MRI is a diagnostic tool where an MRI machine uses a magnetic field to generate images of various parts of the body. A few women may have to undergo MRI during pregnancy to determine fetal health and to examine any specific health conditions, depending on your doctor’s recommendations.

An MRI scan does not expose your body to ionizing radiation, which is a harmful type of radiation found in CT scans, PET scans, and X-rays. It makes MRI a safe diagnostic tool for pregnant women, especially in cases where an ultrasound scan alone is insufficient for examinations. Read this post to know the need for an MRI during pregnancy, its risk factors, limitations, and potential alternatives.”

Why You May Need An MRI During Pregnancy

MRI is a non-invasive image acquisition tool and does not involve surgery. A doctor may order an MRI scan during pregnancy if (2) (3) (4):

  • You need early treatment following a health ailment.
  • The ultrasound is unable to provide sufficient details.
  • More information is required on a baby’s placenta, brain, airway, lungs, and abdomen.
  • More information is required to rule out the chances of visible congenital disabilities.

MRI can be safely used during pregnancy and breast feeding. MRI is done during pregnancy and lactation to (3) (5) (6):

  • Image soft tissues, which is not possible using a CT scan.
  • Have a multi-plane understanding of the tissue.
  • Better understand clinical features with clear images using contrast capabilities. MRI can be performed in contrast enhancement mode to have more explicit images. There are two kinds of contrast enhancement for MRI:
  • Gadolinium-based agents: They are contrast enhancement agents. Gadolinium-enhanced MRI images with better contrast can help understand the fetal nervous system, airway, lungs, abdomen, placental abnormalities, and birth defects.
  • Superparamagnetic iron oxide particles: The application of superparamagnetic iron oxide during human pregnancy is limited due to insufficient animal studies and human trials.
  • Image with contrast enhancement during the lactation. Although there is a risk of gadolinium enrichment in human breast milk during lactation, there are no visible health effects on the baby.

Is It Safe To Have An MRI During Pregnancy?

According to the American College of Obstetricians and Gynecologists (ACOG), it is safe to have an MRI scan during pregnancy (5). According to the University of California, San Francisco, an MRI scan can be conducted in the first, second, or third trimesters without worrying about any health concerns (4).

Further, ACOG recommends physicians order the diagnosis judiciously and only when it is expected to answer some clinically relevant questions (5).

MRI can image deep soft tissue without using any ionizing radiation. According to ACOG, there is no specific precaution for pregnant women to perform an MRI diagnosis. As the technique generates heat and warms the external tissue, there is a concern about its effects on the fetus. However, since the fetus remains deep inside, there is no evidence of actual harmful effects (5).

What Are The Risk Factors Associated With MRI During Pregnancy?

Although the MRI is a safe and effective method of diagnosis, in rare cases, adverse outcomes have been reported with the use of MRI during pregnancy. Some of the associated risks are (3) (4) (7):

  • Gadolinium agents used for contrast enhancement in MRI can have deleterious effects and may cause poor pregnancy outcomes. Therefore, ACOG recommends contrast enhancement only when the benefits outweigh the risks.
  • Human studies suggest that exposure to gadolinium agents can increase the
  • risk of stillbirth and neonatal death in rare cases.
  • Gadolinium agents may cause systemic fibrosis and harm the fetus.
  • The use of gadolinium agents during pregnancy is linked to increased incidence of rheumatological and inflammatory skin in children post-delivery.
  • An MRI exam can be a stressful experience for a pregnant woman. You might be worried about your baby’s health conditions, and it could make you anxious.
  • MRI exposure in the first trimester is shown to have a teratogenic effect (fetal abnormality) in some cases.

What Are The Limitations Of Performing MRI During Pregnancy?

Some of the limitations associated with performing an MRI during pregnancy are (6):

  • Since an MRI scan takes a long time, the artifacts from the moving fetus can lead to errors in image interpretation.
  • Interpretation of fetal MRI is difficult and requires experience.
  • Costlier than ultrasound.
  • May not be available at all places since it requires sophisticated machinery and trained operators.
  • Difficult to position pregnant women inside an MRI scanner comfortably.

What Are The Available Alternatives To MRI During Pregnancy?

Medical imaging study is helpful in the diagnosis of maternal and fetal health and predicting pregnancy outcomes. The alternatives to MRI during pregnancy are (1):

  • Ultrasound: The ultrasound is a safe and effective way of diagnosis during pregnancy. It uses ultrasonic sound to create images. The technique is helpful to understand the fetal developmental milestones and predict the pregnancy outcomes. Ultrasound is the method of choice for estimating fetal gestational age and body weight.
  • CT scan: A CT scan is a powerful tool for clinical diagnosis. It can be safely conducted during pregnancy, but it involves X-ray exposure.

Frequently Asked Questions

1. I had an MRI before I knew I was pregnant. Could it have harmed my baby?

MRI is a safe and effective method of clinical diagnosis and has rare adverse effects (5). If you had undergone an MRI scan earlier, there is nothing to worry about. Your doctor would have carefully evaluated risks
and benefits. Long-term studies have shown that (4) (8):

  • The loud noise of the MRI machine may not cause hearing loss in the fetus.
  • The radiating heat MRI machine may not harm your fetus.
  • First-trimester MRI does not increase any risk of vision loss, congenital anomalies, or neoplasm (tumor).

2. Does an MRI use contrast?

An MRI scan can be performed without contrast, and it is equally valuable. However, when performed along with contrast, the images are easy to interpret with reduced artifacts.

An MRI is a non-invasive diagnostic tool that can be safely performed at any time in pregnancy. It helps understand maternal and fetal complications during pregnancy if ultrasound cannot provide sufficient information. The limited availability and higher cost of the procedure limit its widespread usage. Nevertheless, many hospitals have now introduced MRI machines to enable regular health checkups for pregnant women.

References:

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Anshuman Mohapatra

Anshuman Mohapatra is a biotechnology scientist with more than six years of research experience in analytical chemistry and biotechnology. He has submitted his Ph.D thesis at the Indian Institute of Technology Guwahati (IIT Guwahati) and served as a research fellow (JRF/SRF) during his Ph.D tenure. His research interest includes analytical chemistry, neurobiology and lipid disorder diseases. Three of his research... more