From the Guidelines
Chest X-rays during the second and third trimesters of pregnancy are not associated with significant risk of fetal anomalies, and the benefits of diagnosing and treating maternal conditions often outweigh the minimal radiation risk to the fetus during later pregnancy stages. The radiation dose from a standard chest X-ray is approximately 0.0005-0.01 mGy to the fetus, which is well below the threshold of 50-100 mGy that has been linked to fetal harm 1. After the first trimester, the major organ systems have already formed, making the fetus less susceptible to radiation-induced malformations. However, while the risk is minimal, the ALARA principle (As Low As Reasonably Achievable) should still be followed, meaning X-rays should only be performed when medically necessary. Some key points to consider:
- Fetal doses between 50 and 500 mGy are associated with detectable increased frequencies of all of the adverse fetal effects, but a standard chest X-ray delivers far less than 20 mGy to the uterus 1
- The American College of Radiology (ACR) provides guidance about the need to screen for pregnancy prior to performing a diagnostic test involving ionizing radiation, but chest radiography during the first and second trimesters, and extremity or head and neck radiography, may not be altered by pregnancy status and would not require pregnancy testing 1
- Protective shielding of the abdomen and pelvis should be used when possible, and alternative imaging modalities like ultrasound or MRI should be considered if they can provide the needed diagnostic information
- Diagnostic x-rays pose no risk to lactation, and lactating women do not need to discontinue breastfeeding after receipt of intravascular iodinated contrast 1
- For nuclear imaging, there are concerns about the administration of radioactive iodine, but Tc-99m, which has a shorter half-life, will cause less fetal exposure 1. It is essential to weigh the risks and benefits of any diagnostic test involving ionizing radiation during pregnancy, and to follow the screening and counseling recommendations established for other ionizing radiation imaging 1. If a chest X-ray is clinically indicated during pregnancy, it should not be withheld due to unfounded concerns about fetal anomalies.
From the Research
Association of Chest X-ray Radiation with Fetal Anomaly
- The association between chest X-ray radiation in the 2nd and 3rd trimester and fetal anomaly is a concern due to the potential risks of radiation exposure to the fetus 2, 3.
- Fetuses are more sensitive to radiation due to their rapidly developing cell system, and radiation exposure can lead to slow growth and development, abortion, malformations, impaired brain function, and abnormal childhood growth 2.
- However, the risks of chest X-ray radiation can be limited to safe levels, and alternative non-ionizing radiation methods can be considered to minimize exposure 3.
- In cases where diagnostic imaging is clinically warranted, such as COVID-19 evaluation, chest imaging can be performed with dose optimization strategies to minimize radiation exposure 4.
Alternative Diagnostic Tools
- Chest ultrasound (US) can be a useful diagnostic tool for detecting and monitoring respiratory diseases in pregnant women, avoiding excessive X-rays exposure 5.
- Ultrasound is a safe and effective tool for diagnosing and monitoring pregnancy-related complications, including ectopic pregnancy, placental issues, and presenting parts during the second and third trimesters 6.
- The use of ultrasound and other alternative diagnostic tools can help minimize the risks associated with radiation exposure from chest X-rays and other imaging modalities 5, 6.