Is CT Scan Safe During Pregnancy?
A research-backed, plain-English answer plus the modifications and warning signs that matter.
The short answer
Standard abdominal CT exposes the fetus to under 35 mGy — well below the threshold for harm.
What the research and physiology say
CT scans use ionizing radiation to create detailed cross-sectional images. The radiation dose varies dramatically by the body area scanned — a head CT exposes the fetus to very little radiation (the beam is far from the abdomen), while an abdominal CT exposes the fetus to a measurable but still typically safe dose (usually 25-35 mGy, well below the 50-100 mGy threshold associated with measurable fetal harm). The decision is always a risk-benefit calculation: when CT is medically necessary, the diagnostic benefit usually outweighs the small radiation risk. When alternative imaging (MRI or ultrasound) can answer the clinical question, that is preferred.
How to make it safer (or skip it well)
Tell the radiologist and tech you are pregnant. They will use the lowest possible radiation dose protocol and shield the abdomen with lead if the area being imaged is far from the uterus. For abdominal CT, the shielding cannot eliminate exposure but the dose is still typically safe. Ask the ordering physician whether MRI or ultrasound could provide the needed information instead — sometimes yes, sometimes no.
Warning signs — stop and call your provider
If you had a CT scan before knowing you were pregnant, tell your provider — most exposures are below clinically significant thresholds. If you had an abdominal CT during pregnancy, your provider may want to discuss the radiation dose and any extra monitoring, though most fetal outcomes remain reassuring.
What the medical bodies say
ACOG and the American College of Radiology have joint guidelines stating that CT scans should be used in pregnancy when clinically necessary, with MRI or ultrasound preferred when they can answer the question. The radiation dose threshold for measurable fetal effects is much higher than typical diagnostic CT doses.
For your partner or support person
If you need a CT for emergency reasons (appendicitis, kidney stone, trauma), the urgency is the priority. A partner can help by managing logistics — childcare for other kids, communication with family — so you can focus on care.
Common misconceptions
People think any radiation exposure during pregnancy is dangerous. Diagnostic CT doses are generally below the threshold for measurable effects. Another myth: CT and X-ray are the same. CT uses more radiation per scan than a typical X-ray, but the doses are still in a safe range for one-time diagnostic use.
Things to watch for
Defer non-urgent CT. Use MRI or ultrasound when possible.
Safer alternatives
MRI; ultrasound.
Other pregnancy lifestyle questions
Other pregnancy safety lookups
Or visit the Pregnancy Safety Guide to search across all 460+ lookups.