Magnetic resonance imaging (MRI) is a powerful diagnostic tool with the potential to save lives. But it also has risks that need to be considered before any MRI examination, especially during pregnancy. Here are some things you should know about MRIs and pregnancy.
6 Questions You Might Have on the Safety of MRI Scans During Pregnancy
Why is an MRI needed during pregnancy?
MRI exams early in pregnancy are most often done to investigate or diagnose the following conditions:
- abnormality in the uterus, cervix, vagina, bladder, uterine ligaments (broad or uterosacral ligament), adnexa (ovary)
- early pregnancy bleeding
- pain or concerning symptoms early in pregnancy
- abnormal early second trimester uterine and/or adnexal findings on ultrasound exam
An MRI can provide information about the cause of these problems and guide treatment.
MRI is considered to be safe with modern scanners for any trimester of pregnancy when medically necessary. Studies have shown that there are no harmful effects on the fetus when used appropriately for medical diagnosis.
It is important to remember that an abnormal finding requires careful follow-up with your doctor so you can receive proper care and treatment during your pregnancy. As with any test, an MRI should not be ordered if it does not answer a question or address a clinical need.
Are there special safety concerns with an MRI examination during pregnancy?
During a magnetic resonance imaging exam, the patient is placed in a strong magnetic field. The scanner uses radio waves and a computer to make images of organs, soft tissues, bone, and virtually all other internal body structures. While advances in MRI technology have made it one of the safest diagnostic tools available for patients, some health risks are associated with the use of certain devices.
Researchers continue to study whether MRIs may cause harm to pregnant women or their developing babies. However, according to Radiologyinfo.org, thousands of pregnant women have received MRI tests over the previous 30 years, with no known adverse effects on the fetus.
Compared to most other diagnostic imaging techniques, MRI is not associated with any known health risks. No negative effects on the unborn child have been shown when MRI is used during early pregnancy, and there are no documented reports of harm to pregnant women or their babies from MRI procedures.
If I’m pregnant, what should I expect during the MRI?
Talk to your doctor, so they know you are pregnant. While MRI scans are safe for pregnant women, your doctor should know about the pregnancy before the scan is scheduled.
Oftentimes, MRI scans require a contrasting agent injected into a vein to create bolder contrast and illuminate any issues. Contrasting agents typically contain gadolinium or superparamagnetic iron oxide. Unfortunately, there have not been any studies done on the safety of the agents in pregnant women and fetuses, so unless they’re absolutely necessary, most doctors recommend not using the contrasting agents.
When is an early pregnancy MRI exam recommended?
There is a considerable body of evidence out there indicating that MRIs are safe in the first trimester. Unfortunately, gadolinium may have a side effect of causing vision problems for a developing fetus, so it is recommended that contrasting agents are not used on pregnant women. There were no indications that an MRI could cause a spontaneous abortion for pregnant women in the first trimester. Many women undergo early pregnancy scans, which, unlike MRIs, involve a high degree of radiation exposure (which increases as gestational age increases). As always, discuss your concerns and needs with your family physician and/or referring healthcare provider before undergoing any type of scan.
What can I expect during an MRI when I am further along in my pregnancy?
As gestational age increases during the second and third trimesters of pregnancy, there is increased fetal anatomic detail that may be better assessed by MRIs.
Special MRI techniques, such as diffusion-weighted imaging or MR angiography, require special equipment and personnel who are trained and skilled with specific adjustments for pregnancy patients. These may be best performed within a few weeks of expected delivery due to altered anatomy during early pregnancy. However, additional training and expertise are available at many centres that may allow early pregnant women to undergo these specialized studies such as those used for early identification of fetal anomalies such as neural tube defects, so make sure you book a private MRI scan early on.
What other safety considerations should I make before choosing an early pregnancy MRI?
Because bone tissue can potentially absorb surrounding tissues differently than other types of tissue (such as muscle, ligaments), there is a theoretical risk of early bone development being affected by the magnetic field used during early pregnancy scans. However, no evidence exists that early stages of fetal bone development are at risk for harm from early pregnancy MRIs.
What about MRI and breastfeeding?
There is also no known effect on fertility or on postpartum depression. When it comes to breastfeeding, we still suggest practising caution and discussing with your healthcare provider before undergoing any procedure early in lactation (first six weeks). Unlike during pregnancy, MRIs with contrasting agents are suitable for breastfeeding women.
Even though early pregnancy MRIs are very safe, there are some risks to consider when making decisions about early pregnancy scans. Proceed with caution by asking your doctor or radiologist about all risks involved with early pregnancy MRI exams before scheduling one for yourself or a loved one.
