10 Feb, 2023

MRI in Pregnancy: Your Comprehensive Guide to the Safety, Benefits, and Risks

Pregnancy is a time of great excitement and anticipation, but also of uncertainty as well. Naturally, parents-to-be are conscious of their health and that of their unborn baby, and sometimes decisions need to be made to support the care of the pregnant person, the baby, or both.

One such decision is whether MRI scans are safe during pregnancy. In this blog post, we'll explore the safety considerations, benefits, and risks associated with magnetic resonance imaging during pregnancy.

What is a Magnetic Resonance Imaging (MRI) Scan?

Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic imaging technique used to view internal organs and tissues in detail. It uses a combination of a strong magnetic field, radio waves, and a computer to generate images without the use of X-rays or ionising radiation. For that reason, during MRI, exposure to radiation is not a concern. An MRI scan provides detailed images of organs, soft tissues, muscles and bones inside the body.

Are MRI Scans Safe During Pregnancy?

There is no evidence that suggests MRI in pregnancy poses any risks to the mother or baby. However, your doctor or clinician will be able to offer risk estimates and guidance about MRI safety, all based on the type of scan you need, what you need it for, and how far along in your pregnancy you are.

Some MRI scans require gadolinium contrast material to enhance the scan images, and the use of a gadolinium agent is generally discouraged during pregnancy. In early pregnancy, there is a potentially slightly higher risk of a range of rheumatological and inflammatory conditions than in the third trimester respectively, where a gadolinium agent has been used.

Benefits of Having an MRI Scan During Pregnancy

For the health of the pregnant person, sometimes an MRI scan is the best medical imaging method available to address a healthcare concern that might also affect their pregnancy. Here are some of the benefits of MR imaging during pregnancy.

  • No ionising radiation

    If a pregnant patient needs to undergo a diagnostic imaging procedure, and an ultrasound will not get the patient the answers they need, an MRI may be the next best option. This is because with MRI, exposure to ionising radiation is non-existent. Unlike X-ray or CT scans, an MRI scan can provide detailed images of the inside of your body without radiation risks.

    For the baby, MRI scanning can be useful for diagnostic purposes when it comes to evaluating foetal health and development during pregnancy. With no risk of exposing them to X-ray radiation, there is no relative risk of damage to the developing baby's cells.

  • Safer than CT or X-ray for the unborn baby

    Sometimes there are times when ultrasound scans do not provide the necessary imaging outcomes. This can happen in cases of multiple pregnancies, where some body parts overlap and obscure each other, or when more complex imaging of the brain or spine is required to detect congenital anomalies. MR imaging safety concerns are low, making an MRI scan the next best option during pregnancy compared to a CT or X-ray, if an ultrasound is not conclusive.

  • Pregnant women may need diagnoses during pregnancy to maintain their own health

    Magnetic resonance imaging is a key diagnostic imaging method used to identify a range of conditions that could affect the mother's health, and therefore the baby's health.

    For example, there may be times when a pregnant person falls ill, and in order to access treatment, they need a scan to identify the issue. This could be anything from a lump or tumour to damage to the spine, or even soft tissue and other musculoskeletal issues, and MRI may be the safest option to get answers during pregnancy.

What Are The Risks Of Undergoing An MRI Scan While Pregnant?

According to Radiology Info, MRI scans pose no known risks to pregnant women or unborn babies. However, it is important to seek advice from your doctor or clinician to ensure you are aware of all the potential risks, and in many cases, it might be recommended to wait until after childbirth before having your MRI scan.

There are some possible risks associated with MRI scans that should be taken into account:

  • The use of gadolinium contrast media

    Gadolinium contrast media is sometimes, but not always, used to highlight or define certain parts of the body in MRI scan images. It is usually administered via injection during MRI procedures.

    There is a potential risk that gadolinium crosses the placenta and affects the fetal kidneys, and then recirculates via the amniotic fluid. This has the potential to cause infiltrative skin conditions such as nephrogenic systemic fibrosis (NSF), and could cause a marginally increased risk of neonatal death. However, these are extremely uncommon outcomes.

  • The use of strong magnetic fields and radio frequencies

    MRI scans are called Magnetic Resonance Imaging because they use very strong magnets, and the strength of the magnetic field depends on the type of scanner. 1.5T MRI scanners have half the magnetic strength of a 3.0T MRI scanner. Radio frequencies are also used during the scan.

    There are some concerns in the medical profession that the heating effect of the scanner's technology could pose a risk to the unborn baby, especially during the first trimester MRI. However, there is no evidence to prove this, and studies that assess uncommon outcomes have shown no risk of birth defects or adverse outcomes linked to MRI in pregnancy.

  • High levels of noise

    In the MR scan room, it can get very noisy during the procedure. While pregnant patients can wear earplugs to protect their hearing and reduce any anxiety caused by this, there could be a risk to the hearing of the unborn baby. However, based on some small studies, damage to foetal hearing has not been reported, and findings suggest no known risk of hearing loss. Further studies could help identify whether the risks are statistically significant.

It is important to remember that MRI safety considerations also apply to pregnant health care practitioners, who can enter the MR scan room for positioning patients but should not remain near the MR scanner bore during the scan itself.

Do gadolinium-based contrast agents affect breast milk?

It is worth bearing in mind that if a person has an MRI scan while breastfeeding or close to birth, less than 1% of the gadolinium contrast media enters the breast milk. It is generally not necessary to interrupt breastfeeding after having a gadolinium-enhanced MRI scan.

What happens if you get an MRI and didn't know you were pregnant?

As the risks of magnetic resonance imaging to unborn babies are very low, it is unlikely that having a scan while unknowingly being pregnant would be a cause for concern. If you had a scan with a gadolinium-based contrast medium, the risks of adverse outcomes are still extremely uncommon.

It is worth consulting with your doctor if you are feeling worried about the effects of MRI on your unborn baby, as they will be able to reassure you and monitor any concerns that you have.

Can I have an MRI scan while pregnant?

Ultimately, seeking advice from your doctor or clinician is the best first step to finding out whether MRI exposure is suitable for your pregnancy.

At Scan.com, our ability to scan pregnant patients depends on the criteria set by our partner scanning centres, along with how far along in your pregnancy you are, and the reason you need to have a scan. Every booking includes 1-1 clinician guidance, where our team will be able to help you decide what the best next steps are.

Next steps

At Scan.com, we offer both private MRI scans and pregnancy ultrasound scans. With easy online booking, you can quickly get the scan that's right for you.

Visit our news page for more information about radiology, scan types, and how scans are used in healthcare.

Sources used

https://radiology.ucsf.edu/patient-care/patient-safety/ct-mri-pregnancy#accordion-pregnantemployees-inmri-environment

https://mothertobaby.org/fact-sheets/magnetic-resonance-imaging-mri/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3470645/

https://www.breastfeedingnetwork.org.uk/mri/

https://jamanetwork.com/journals/jama/fullarticle/2547756

https://www.radiologyinfo.org/en/info/safety-mri-pregnancy

https://www.nhs.uk/conditions/mri-scan/who-can-have-it/

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