+ Risks of MRI for the pregnant patient
- Patients in the first trimester of pregnancy might be more susceptible to potential adverse effects including:1,2
- Possible bioeffects of the static magnetic field
- Risks associated with exposure to gradient magnetic fields
- Potential adverse effects of radiofrequency (RF) energy
- Possible adverse effects related to the combination of all three magnetic fields
- In order to properly assess risk with regard to pregnancy, it is recommended that every female patient of childbearing age (between 11-55 years) is asked before a procedure if there is a possibility that she is pregnant.3,4
+ Appropriate use of MRI in pregnant women
- MRI may be used in pregnant women if other non-ionizing forms of diagnostic imaging are inadequate or if the examination provides important information that would otherwise require exposure to ionizing radiation.1,5
- Before proceeding with MRI, the healthcare team considers the following questions:1
- Would sonography be satisfactory for diagnosis?
- Is the MR procedure appropriate to address the clinical question?
- Is early delivery a consideration?
- Is termination of the pregnancy a possibility?
- MRI should not be withheld when the benefits of the examination clearly outweigh the risks, such as in the following cases:1
- Brain and spine symptoms requiring imaging
- Cancer requiring imaging
- Chest, abdominal and pelvic signs and symptoms of active disease where sonography results are inconclusive
- Specific, suspected cases of fetal anomaly or complex fetal disorder
+ Obtaining informed consent
- Informed consent is obtained by the radiologist, prior to initiating the exam.
- A consent form is signed by both the patient and the radiologist
+ MRI with contrast
- Gadolinium enhancement is best avoided when examining the pregnant patient.2
- Research on the risks posed by gadolinum-based contrast for pregnant mothers is limited, and there is insufficient evidence to conclude that it poses no risk to the fetus1
- If it is absolutely necessary to proceed using a contrast agent, a consent form is signed by the patient following an informed consent process which includes an explanation of the potential risks and benefits by the radiologist.
- Pregnant patients are informed that current data shows MRI to be relatively safe for pregnant women with no evidence of deleterious effects in the literature.1
- If the patient is to undergo a procedure requiring gadolinium-based contrast, an explanation is provided regarding the risks of contrast media and the precautions that are being undertaken to avoid unnecessary exposure to risk.
- Shellock FG. Reference Manual for Magnetic Resonance Safety, Implants, and Devices. 2012 Ed. Los Angeles, CA: Biomedical Research Publishing Group; 2012.
- Westbrook C, Kaut Roth C, Talbot J. MRI in Practice. 3rd Ed. London, UK: Blackwell Publishing Ltd.; 2005.
- Martensen, Kathy. Radiographic Image Analysis. St Louis, 2011, Saunders Elesvier.
- Health Canada. Safety Code 35: Safety Procedures for the Installation, Use and Control of X-ray Equipment in Large Medical Radiological Facilities. Available at: http://www.hc-sc.gc.ca/ewh-semt/pubs/radiation/safety-code_35-securite/index-eng.php. Accessed April 30, 2013.
- Kanal E, et al. American College of Radiology White Paper on MRI safety. AJR 2007;188:1–27.