Many things are especially important during pregnancy, such as eating right, cutting out cigarettes and alcohol, and being careful about the prescription and over-the-counter drugs you take. Diagnostic x -rays and other medical radiation procedures of the abdominal area also deserve extra attention during pregnancy.
There is scientific disagreement about whether the small amounts of radiation used in diagnostic radiology can actually harm the unborn child, but it is known that the unborn child is very sensitive to the effects of things like radiation, certain drugs, excess alcohol, and infection. If radiation or other agents were to cause changes in these cells, there could be a slightly increased chance of birth defects or certain illnesses, such as leukemia, later in life.
It should be pointed out, however, that the majority of birth defects and childhood diseases occur even if the mother is not exposed to any known harmful agent during pregnancy. Scientists believe that heredity and random errors in the developmental process are responsible for most of these problems.
There are, however, rare situations in which a woman who is unaware of her pregnancy may receive a very large number of abdominal x -rays over a short period. This is important for many medical decisions, such as drug prescriptions and nuclear medicine procedures, as well as x -rays.
In fact, the American College of Obstetricians and Gynecologists (COG) recommends that pregnant women maintain good oral health by keeping up with such routine dental procedures as X -rays, teeth cleaning, cavity-filling, and root canals. It's a still a good idea to use a leaded apron to protect your abdomen to minimize your baby's radiation exposure when you've having other parts X-rayed.
There are some kinds of X -rays (such as those used to treat disease) that may expose your baby to high doses of radiation, which can cause miscarriage or birth defects as well as some cancers in later life. Ultrasounds use sound waves to see your organs and blood flow.
Magnetic resonance imaging (MRI) uses a magnetic field, radio waves, and computer software to produce highly detailed images of organs and structures in your body. X -rays use a small dose of radiation, usually in the form of light or radio waves, to create black and white images of the inside of the body.
Computed tomography (CT, or CAT scan) puts together X -rays taken from multiple angles to create more detailed 3D images. Magnetic resonance imaging (MRI) scans are known to be on the safer side.
Even though MRIs are not considered risky, organizations like the American College of Obstetricians and Gynecologists still recommend using them sparingly, and only when medically necessary. There's always the possibility that research could identify harmful effects in the future.
Here's the problem: CT Scans, X -rays, and tests that include X -rays all use ionizing radiation. Even though the amount of radiation in these tests is very small, and usually won't cause harm to a fetus, there are still some risks, such as birth defects.
That's why your provider may recommend tests involving X -rays even if you're pregnant. When your health is in jeopardy, and ultrasounds or MRIs aren't enough or are unavailable, it's usually recommended that you get the test you need. Your provider will go over the pros and cons of getting the test. It also depends on the part of your body that needs imaging.
At UVA Radiology and Medical Imaging, we want to give you all the information you need to work with your doctor and make the best decision for you AND your baby. And it is important to keep in mind that the benefit of allowing your doctor to have a clear image of your medical condition most likely outweighs any potential risk to you or your baby.
This document reflects emerging clinical and scientific advances as of the date issued and is subject to change. ABSTRACT: Imaging studies are important adjuncts in the diagnostic evaluation of acute and chronic conditions.
Ultrasonography and magnetic resonance imaging (MRI) are not associated with risk and are the imaging techniques of choice for the pregnant patient, but they should be used prudently and only when use is expected to answer a relevant clinical question or otherwise provide medical benefit to the patient. If these techniques are necessary in addition to ultrasonography or MRI or are more readily available for the diagnosis in question, they should not be withheld from a pregnant patient.
Imaging studies are important adjuncts in the diagnostic evaluation of acute and chronic conditions. Ultrasound imaging should be performed efficiently and only when clinically indicated to minimize fetal exposure risk using the keeping acoustic output levels As Low As Reasonably Achievable (commonly known as CLARA) principle.
There have been no reports of documented adverse fetal effects for diagnostic ultrasonography procedures, including duplex Doppler imaging. The U.S. Food and Drug Administration limits the spatial-peak temporal average intensity of ultrasound transducers to 720 mW/cm2.
However, it is highly unlikely that any sustained temperature elevation will occur at any single fetal anatomic site 3. Those configured for use in obstetrics do not produce the higher temperatures delivered by machines using nonobstetric transducers and settings.
Similarly, although color Doppler in particular has the highest potential to raise tissue temperature, when used appropriately for obstetric indications, it does not produce changes that would risk the health of the pregnancy. However, the potential for risk shows that ultrasonography should be used prudently and only when its use is expected to answer a relevant clinical question or otherwise provide medical benefit to the patient 5.
When used in this manner and with machines that are configured correctly, ultrasonography does not pose a risk to the fetus or the pregnancy. The principal advantage of MRI over ultrasonography and computed tomography is the ability to image deep soft tissue structures in a manner that is not operator dependent and does not use ionizing radiation.
Magnetic resonance imaging is similar to ultrasonography in the diagnosis of appendicitis, but when MRI is readily available, it is preferred because of its lower rates of nonvisualization 6. Although there are theoretical concerns for the fetus, including teratogenesis, tissue heating, and acoustic damage, there exists no evidence of actual harm.
Finally, available studies in humans have documented no acoustic injuries to fetuses during prenatal MRI 1. In considering available data and risk of teratogenicity, the American College of Radiology concludes that no special consideration is recommended for the first (versus any other) trimester in pregnancy 8.
Unlike CT, MRI adequately images most soft tissue structures without the use of contrast. The longer gadolinium-based products remain in the amniotic fluid, the greater the potential for dissociation from the ch elate and, thus, the risk of causing harm to the fetus 8.
This study interrogated a universal health care data-base in the province of Ontario, Canada to identify all births of more than 20 weeks of gestation, from 2003 to 2015. The risk also was not significantly higher for congenital anomalies, neoplasm, or vision or hearing loss.
Stillbirths and neonatal deaths also occurred more frequently among 7 gadolinium MRI-exposed versus 9,844 MRI unexposed pregnancies (adjusted RR, 3.70; 95% CI, 1.55–8.85). Limitations of the study assessing the effect of gadolinium during pregnancy include using a control group who did not undergo MRI (rather than patients who underwent MRI without gadolinium) and the rarity of detecting hematologic, inflammatory, or infiltrate skin conditions 12.
Given these findings, as well as ongoing theoretical concerns and animal data, gadolinium use should be limited to situations in which the benefits clearly outweigh the possible risks 812. To date, there have been no animal or human fetal studies to evaluate the safety of super paramagnetic iron oxide contrast, and there is no information on its use during pregnancy or lactation.
If extremely high-dose exposure (in excess of 1 GY) occurs during early embryogenesis, it most likely will be lethal to the embryo 1516. In humans, growth restriction, microcephaly, and intellectual disability are the most common adverse effects from high-dose radiation exposure 217.
In rare cases in which there are exposures above this level, patients should be counseled about associated concerns and individualized prenatal diagnostic imaging for structural anomalies and fetal growth restriction 16. A 10–20 may fetal exposure may increase the risk of leukemia by a factor of 1.5–2.0 over a background rate of approximately 1 in 3,000 720.
Computed tomography is a specific use of ionizing radiation that plays an important diagnostic role in pregnancy, and its use increased by 25% per year from 1997 to 2006 1. Use of CT and associated contrast material should not be withheld if clinically indicated, but a thorough discussion of risks and benefits should take place 8.
In the evaluation for acute processes such as appendicitis or small-bowel obstruction, the maternal benefit from early and accurate diagnosis may out-weigh the theoretical fetal risks. If accessible in a timely manner, MRI should be considered as a safer alternative to CT imaging during pregnancy in cases in which they are equivalent for the diagnosis in question.
Radiation exposure from CT procedures varies depending on the number and spacing of adjacent image sections. In the case of suspected pulmonary embolism, CT evaluation of the chest results in a lower dose of fetal exposure to radiation compared with ventilation-perfusion scanning 2.
Oral contrast agents are not absorbed by the patient and do not cause real or theoretical harm. The use of intravenous contrast media aids in CT diagnosis by providing for enhancement of soft tissues and vascular structures.
The contrast most commonly used for CT is dominated media, which carries a low risk of adverse effects (e.g., nausea, vomiting, flushing, pain at injection site) and anaphylactic reactions 9. Although dominated contrast media can cross the placenta and either enter the fetal circulation or pass directly into the amniotic fluid 22, animal studies have reported no teratogenic or mutagenic effects from its use 822.
Additionally, theoretical concerns about the potential adverse effects of free iodide on the fetal thyroid gland have not been borne out in human studies 17. Despite this lack of known harm, it generally is recommended that contrast only be used if absolutely required to obtain additional diagnostic information that will affect the care of the fetus or woman during the pregnancy.
Traditionally, lactating women who receive intravascular dominated contrast have been advised to discontinue breastfeeding for 24 hours. Nuclear studies such as pulmonary ventilation-perfusion, thyroid, bone, and renal scans are performed by “tagging” a chemical agent with a radioisotope.
This type of imaging is used to determine physiologic organ function or dysfunction rather than to delineate anatomy. In pregnancy, fetal exposure during nuclear medicine studies depends on the physical and biochemical properties of the radioisotope.
In general, these procedures result in an embryonic or fetal exposure of less than 5 may, which is considered a safe dose in pregnancy. The half-life of this radioisotope is 6 hours, and it is a pure gamma ray emitter, which minimizes the dose of radiation without compromising the image 9.
Article Locations: Patel SJ, Reed DL, Katz DS, Subramaniam R, Amorous JK. Article Locations: American Institute of Ultrasound in Medicine.
Article Locations: Thales LH, Selznick VM, Long man RE, Truly MG, Ohio AO, Mac ones GA, et al. Utility of magnetic resonance imaging for suspected appendicitis in pregnant women. Article Locations: Baedeker JR, Gorengaut V, Brown JJ.
Article Locations: Canal E, Markovic AJ, Bell C, Forested JP, Bradley WE Jr, Frolic JR, et al. ACR guidance document on MR safe practices: 2013. Article Locations: Adam A, Dixon AK, Gillard JR, Schaefer-Prokop CM, editors.
Article Locations: De Santos M, Surface G, Cavalier AF, Caducei B, Caruso A. Gadolinium periconceptional exposure: pregnancy and neonatal outcome. Ray JG, Vermeulen MJ, Bharat ha A, Montana WE, Park AL. Association between MRI exposure during pregnancy and fetal and childhood outcomes.
Article Locations: At well TD, Leaf AN, Brown DL, McCann M, Townsend JE, Leroy AJ. Neonatal thyroid function after administration of IV dominated contrast agent to 21 pregnant patients.
Article Locations: Blot WE, Miller RAW. Discussion: severe mental retardation and cancer among atomic bomb survivors exposed in uteri.
Article Locations: Gjelsteen AC, Ching BH, Maryann MW, Prayer DA, Murphy TF, Betray BD, et al. CT, MRI, PET, PET/CT, and ultrasound in the evaluation of obstetric and gynecologic patients. Article Locations: Green RS, BAE BY, LIM KJ.
Article Locations: Webb JA, Thomsen HS, Marcos SK. Members of Contrast Media Safety Committee of European Society of Urogenital Radiology (ESR).
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The American College of Obstetricians and Gynecologists 409 12th Street, SW, PO Box 96920, Washington, DC 20090-6920 Variations in practice may be warranted when, in the reasonable judgment of the treating clinician, such course of action is indicated by the condition of the patient, limitations of available resources, or advances in knowledge or technology.
COG does not guarantee, warrant, or endorse the products or services of any firm, organization, or person. Neither COG nor its officers, directors, members, employees, or agents will be liable for any loss, damage, or claim with respect to any liabilities, including direct, special, indirect, or consequential damages, incurred in connection with this publication or reliance on the information presented.