X-ray Safety During Pregnancy

Radiation Risk Assessment

Fetal doses below 50 mGy are not associated with detectable increases in adverse fetal outcomes 1
Most diagnostic X-ray studies deliver far less than 20 mGy to the uterus, including single-phase CT studies of the abdomen 2
The threshold for significant risk of fetal damage is set at 100 mGy 3
Simple X-rays with proper abdominal shielding carry negligible fetal radiation exposure of <0.1 mGy 3

Chest radiography during first and second trimesters, and extremity or head/neck radiography, may be performed safely with minimal fetal risk 2
Abdominal/pelvic imaging with X-rays should be avoided when possible due to direct fetal exposure 4
CT imaging of the abdomen and pelvis is not supported as initial imaging in pregnant patients due to ionizing radiation risk to the embryo/fetus 5

Ultrasound and MRI are preferred imaging modalities during pregnancy as they do not use ionizing radiation 3, 4
MRI is generally safe in pregnancy and can be useful for detecting various conditions without exposing the fetus to radiation 5
MRI without contrast is preferred; gadolinium-based contrast agents should be avoided during pregnancy unless absolutely necessary 5, 4

The medical necessity of the examination must outweigh potential risks to the fetus 2

All women of childbearing age (typically 12-50 years) should be questioned about pregnancy status before imaging 2
For high-dose procedures like fluoroscopy, pregnancy testing within 72 hours is recommended unless medical urgency prevents it 2
Proper shielding of the abdomen should be used whenever possible to minimize fetal exposure 3, 6
The ALARA principle (As Low As Reasonably Achievable) should be followed to minimize radiation exposure 6

Diagnostic X-rays pose no risk to lactation, and lactating women do not need to discontinue breastfeeding after receiving intravenous iodinated contrast 2
Special consideration is needed for nuclear medicine procedures, particularly those using radioactive iodine, which can cross the placenta and affect the fetal thyroid after 12 weeks gestation 2

The American College of Radiology recommends that CT abdomen and pelvis without contrast should be avoided in pregnant women due to radiation exposure risks to the fetus and should only be performed when the potential benefits far outweigh the risks in life-threatening situations 7, 8

The American College of Radiology recommends ultrasound as the first-line imaging modality for pregnant patients due to its lack of ionizing radiation 7, 9
The American College of Radiology recommends MRI without contrast as the preferred second-line imaging modality when ultrasound is inadequate or inconclusive 10, 11
MRI does not expose the embryo or fetus to ionizing radiation and can effectively detect various conditions 9, 10

For microhematuria evaluation in pregnancy, the American College of Radiology recommends ultrasound as the initial imaging modality, and notes that the incidence of malignancy is low in pregnant women with microhematuria 7
For suspected acute pyelonephritis in pregnancy, the American College of Radiology recommends ultrasound as the preferred initial imaging modality, and does not support CT abdomen and pelvis as initial imaging 9
For suspected adnexal masses in pregnancy, the American College of Radiology recommends avoiding CT pelvis due to radiation dose, and instead using ultrasound followed by MRI without contrast if needed 12, 13

The American College of Radiology suggests that CT may be considered in life-threatening situations where the benefit outweighs the risk, such as major trauma or cases where timely diagnosis is critical for maternal survival 8
A retrospective study of pregnant patients with abdominal pain found that CT showed findings explaining the pain in 36% of cases, with some requiring surgical intervention after normal ultrasound findings 8

The American College of Radiology recommends avoiding gadolinium-based contrast agents for MRI during pregnancy unless absolutely necessary 10, 12