Is a chest X-ray (CXR) indicated in the third trimester of pregnancy?

From the Guidelines

Chest X-rays can be safely performed during the third trimester of pregnancy when medically necessary, with a very low radiation dose of approximately 0.01 mGy, as stated in the ESC Guidelines 1. The benefits of diagnosing potentially serious conditions like pneumonia, tuberculosis, or pulmonary embolism typically outweigh the minimal risks of radiation exposure.

• Proper shielding with a lead apron over the abdomen and pelvis should be used to further minimize fetal exposure.
• Alternative imaging methods like ultrasound or MRI may be considered first when appropriate, but should not delay diagnosis if a chest X-ray is clinically indicated.
• Pregnant patients should be informed about the minimal risks and clear benefits before proceeding, as recommended by the American College of Radiology 1.
• Healthcare providers should document the clinical necessity of the X-ray in the medical record, following the ALARA principle (As Low As Reasonably Achievable) by using the minimum radiation dose needed for adequate imaging, as suggested by the European Society of Cardiology 1 and the American Thoracic Society 1. The most recent and highest quality study, published in 2017 by the Journal of the American College of Radiology 1, supports the use of chest X-rays in pregnant patients with a rating of 9, indicating that it is usually appropriate, with a relative radiation level of ☢.

From the Research

Chest X-Ray in the 3rd Trimester

• The use of chest X-ray (CXR) in the 3rd trimester of pregnancy has been studied in various contexts, including its role in diagnosing neonatal lung diseases 2 and its relationship with the development of preeclampsia in twin pregnancies 3.
• A study published in 2022 found that the incidence of abnormal findings on CXR early in the 3rd trimester of twin pregnancy was 18.2%, and that positive CXR findings were independently associated with subsequent preeclampsia 3.
• However, the use of CXR in pregnancy is not without controversy, and some studies have highlighted the potential risks and limitations of routine ultrasound screening in the 3rd trimester, including the potential for false positive results and unnecessary intervention 4.
• In terms of diagnostic accuracy, a systematic review published in 2025 compared the performance of lung ultrasound, CXR, and CT scans for diagnosing pneumonia, and found that CT scans produced the highest sensitivity, while lung ultrasound was most helpful in pediatric and acute care populations 5.

Diagnostic Accuracy of Chest X-Ray

• The diagnostic accuracy of CXR has been compared to other imaging modalities, including lung ultrasound and CT scans, in various studies 2, 5.
• A study published in 2021 found that both lung ultrasound and CXR have advantages and disadvantages, and that they should serve as complementary diagnostic methods in providing accurate, timely, and reliable information 2.
• Another study published in 2025 found that CT scans were the most accurate type of scan for diagnosing pneumonia, but that they should only be used in more severe interventions due to cost and radiation exposure 5.

Clinical Applications of Chest X-Ray

• CXR has been used in various clinical contexts, including the diagnosis of neonatal lung diseases 2 and the detection of pneumonia 5.
• A study published in 2022 found that CXR abnormalities early in the 3rd trimester of twin pregnancy were associated with an increased risk of subsequent preeclampsia 3.
• However, the clinical applications of CXR are not limited to pregnancy, and it has also been used in the diagnosis and management of chronic obstructive pulmonary disease (COPD) 6.