Brain Imaging During Pregnancy: Weighing The Risks And Benefits

There are many reasons why a doctor might recommend that a pregnant woman have a brain scan. Brain scans can include MRIs, CT scans, and X-rays. While these tests are essential for monitoring, diagnosing, and treating patients, including pregnant women, some pregnant patients might worry about the risks to their unborn baby. However, not all medical imaging exams use radiation, and even if they do, many exams are safer for an unborn baby than you might think.

MRI scans, for example, use strong magnetic waves to produce detailed images of soft tissues like organs, tendons, and joints. Because they use magnetic waves, there are no proven risks to getting an MRI during pregnancy. The American College of Obstetricians and Gynecologists (ACOG) and the American College of Radiology (ACR) have stated that pregnant people can have an MRI done during any trimester.

CT scans and X-rays, on the other hand, do use ionizing radiation. However, receiving a CT scan during pregnancy has not been shown to increase radiation exposure to the fetus. Even though CT scans use more radiation than X-rays, the increase is not enough to create additional risk for an unborn child. Similarly, in almost all cases, getting an X-ray during pregnancy does not expose the fetus to radiation.

Overall, while there may be concerns about the safety of brain scans during pregnancy, the benefits of these scans in monitoring and diagnosing conditions often outweigh the potential risks.

MRI scans are safe during pregnancy but gadolinium-enhanced MRI may increase the risk of a rare vision problem in the baby

Magnetic Resonance Imaging (MRI) is a safe procedure for pregnant women. It does not use ionising radiation like an X-ray or CT scan, but instead uses a magnetic field and radio waves to create images of the inside of the body. MRI scans are painless and do not cause tissue damage.

However, the use of gadolinium-based contrast agents during pregnancy is controversial. Gadolinium is water-soluble and can cross the placenta into the fetal circulation and amniotic fluid. While gadolinium is non-toxic in its chelated (bound) form, it can become toxic if it dissociates from the chelate molecule. The longer the gadolinium remains in the amniotic fluid, the greater the risk of this dissociation.

A study of 1.4 million pregnancies found that gadolinium-enhanced MRI at any time during pregnancy may slightly increase the risk of a rare vision problem in the baby. The risk of stillbirths and neonatal deaths was also higher among those exposed to gadolinium-enhanced MRI compared to those who were not. However, the broader outcome of rheumatological, inflammatory, or infiltrative skin conditions was only slightly increased.

Given these findings, it is recommended that gadolinium contrast agents be avoided during pregnancy unless the benefits clearly outweigh the possible risks.

MRI uses a large magnet, radio waves and a computer to create images of the baby

Magnetic resonance imaging (MRI) is a non-invasive imaging technology that uses a large magnet, radio waves, and a computer to create highly detailed images of the body's internal structures. It is often used for disease detection, diagnosis, and treatment monitoring.

The MRI machine creates a strong magnetic field around the patient and sends pulses of radio waves from a scanner. The strong magnetic field aligns the atoms in the body in the same direction. When the radio waves are turned off, the atoms return to their original position and send back radio signals. These signals are converted into an image of the body part being examined by a computer.

MRI is particularly useful for imaging the non-bony or soft tissues of the body, such as the brain, spinal cord, nerves, muscles, ligaments, and tendons. It is also effective in differentiating between white and grey matter in the brain and can be used to diagnose aneurysms and tumors.

During an MRI scan, the patient is placed inside a large magnet and must remain very still to avoid blurring the image. The process is generally painless, but some people may find it uncomfortable to remain still for an extended period. The machine can also be noisy and cause a feeling of warmth.

While MRI is considered safe for pregnant women, it is generally recommended to avoid MRI scans during pregnancy as a precaution, especially during the first trimester when the fetus's organs are forming. This is because the potential risks to the developing fetus are not yet fully understood, and contrast agents used in the scan could enter the fetal bloodstream. However, if the clinical benefits outweigh the risks, healthcare providers may perform an MRI scan during pregnancy.

MRI is not associated with any known risks to the foetus

Magnetic resonance imaging (MRI) is a vital tool for diagnosing acute and chronic conditions. However, there is often confusion about the safety of these procedures for pregnant and lactating women, which can lead to the unnecessary avoidance of useful diagnostic tests. Ultrasound is the most commonly used imaging exam during pregnancy, but if it does not provide a clear answer, or if other parts of the body need to be imaged, an MRI may be necessary.

MRI uses a large magnet, pulses of radiofrequency waves, and a computer to create images of the foetus. It does not use radiation to capture an image inside the body, and it does not require intravenous contrast material (dye) or sedation.

There are no proven risks to pregnant women or unborn babies from MRI exams. Over the last 30 years, thousands of pregnant women have had MRI exams, and no harmful effects to the baby have been found. The American College of Obstetricians and Gynecologists’ Committee on Obstetric Practice states that "ultrasonography and magnetic resonance imaging (MRI) are not associated with risk and are the imaging techniques of choice for the pregnant patient".

The American College of Radiology's Safety Committee has also issued the following statement: "MR imaging 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 (e.g., fluoroscopy, CT). It is recommended that pregnant patients be informed that, to date, there has been no indication that the use of clinical MR imaging during pregnancy has produced deleterious effects."

While MRI is considered safe for pregnant women and their unborn babies, it is still important to weigh the risks and benefits of any medical procedure. In the case of MRI during pregnancy, the potential benefits of accurate diagnosis and treatment may outweigh the theoretical risks.

Gadolinium-based contrast agents are controversial as they can cross the placenta and enter the fetal circulation

Gadolinium-based contrast agents (GBCAs) are used to improve the visualisation of organs and tissue during MRI scans. They are considered relatively or absolutely contraindicated during pregnancy because they can cross the placenta and enter the fetal circulation. The long-term effects of GBCAs on the fetus are unknown, and the safety of GBCAs for the fetus has not been proven.

GBCAs are excreted almost exclusively by the kidneys through glomerular filtration. They possess a very high safety index in humans. However, gadolinium is water-soluble and toxic in its free form, so it is only administered in a chelated (bound) form. Animal studies have shown that high and repeated doses of GBCAs can be teratogenic, presumably because this allows gadolinium to dissociate from the chelation agent.

In humans, the principal concern with GBCAs is that the duration of fetal exposure is unknown because the contrast present in the amniotic fluid is swallowed by the fetus and re-enters the fetal circulation. The longer GBCAs remain in the amniotic fluid, the greater the potential for dissociation from the chelate and, thus, the risk of harm to the fetus.

The European Society of Radiology has issued a guideline concluding that gadolinium is probably safe during pregnancy, as excessive quantities are not expected to cross the placenta or be toxic to the fetus if they do. The guideline also states that, given that gadolinium is mainly distributed in extracellular water and rapidly eliminated by the kidney, in the unlikely event that some gadolinium reaches the baby, it would be rapidly eliminated into urine.

The use of GBCAs during pregnancy is controversial, and current radiology practices and recommendations discourage their use. However, available evidence suggests it is unlikely that these compounds adversely affect the developing fetus. Therefore, their use should not be limited, particularly given the important clinical reasons for MRI examinations during pregnancy (e.g., to rule out serious abdominal diseases).

To avoid inadvertent administration of GBCAs to pregnant women, radiology imaging centres can implement several measures, such as safety screening forms, direct questioning of women by radiologic technologists, and prominently displayed signs asking women to notify staff if they may be pregnant.

Ultrasound is a preferred method of imaging during pregnancy due to its wide availability, low cost and safety

Brain scans are not recommended during pregnancy, especially those that use ionizing radiation, such as X-rays and CT scans. However, ultrasound scans are considered safe and are routinely used during pregnancy to monitor the health and growth of the baby.

Ultrasound is a preferred method of imaging during pregnancy due to its wide availability, low cost, and safety profile. It is a non-invasive technique that uses sound waves to create images of the baby in the womb. It does not use radiation, such as X-rays, and has no known side effects on mothers or babies. Ultrasound scans can be carried out at any stage of pregnancy and are usually offered at least twice during the pregnancy journey: once in the first trimester and once in the second trimester.

The first ultrasound, also known as a dating scan, is typically done between 11 and 14 weeks of pregnancy. It helps estimate the due date, confirm pregnancy, and check for ectopic pregnancy, miscarriage, or other early complications. The second ultrasound, known as the anomaly scan or mid-pregnancy scan, is usually done between 18 and 22 weeks. This scan checks for physical conditions in the baby, including the heart rate and rhythm, as well as the structure and growth of the baby's organs.

In addition to its safety and wide availability, ultrasound is also preferred due to its low cost. While ultrasounds are not considered cheap, most health insurance plans will cover the cost of prenatal ultrasounds if they are for medical purposes.

Overall, ultrasound is a safe, accessible, and relatively affordable option for imaging during pregnancy, making it the preferred choice for healthcare providers and pregnant individuals.

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