When you're pregnant, your doctor weighs the benefit of a scan against a small risk. They'll favour radiation-free tests (ultrasound, MRI) where possible, but won't withhold a genuinely necessary scan — because sometimes the bigger risk is missing an important diagnosis. Decisions are often made together with the radiologist, who can advise the safest option.
Key takeaways
- Doctors weigh the benefit of a scan against a small risk in pregnancy.
- Radiation-free tests are favoured, but a necessary scan isn't withheld.
- Sometimes the bigger risk is missing an important diagnosis.
- Decisions are often made with the radiologist's input.
Deciding on a scan during pregnancy is a careful balance — and it’s worth understanding how your doctor thinks about it.
Benefit weighed against a small risk
The guiding principle is benefit versus risk. Scans that use radiation are generally avoided in pregnancy, so doctors first look at whether a radiation-free test — ultrasound or MRI — can answer the question.[2]
But they also won’t withhold a genuinely necessary scan, because sometimes the bigger risk is not having the information — for example, missing a serious, treatable problem.[1]
A practical example
A clear example is a suspected blood clot in the lungs (pulmonary embolism). Here, the small dose of a scan is far outweighed by the danger of missing the clot, so the scan is done — with the dose reduced where possible.[2]
Made together
These decisions are often made with the radiologist or nuclear medicine specialist, who can advise the safest test for your situation and adjust the technique.[2]
Questions worth asking
- Is a radiation-free test (ultrasound or MRI) an option?
- If radiation is used, what’s the dose, and how is the baby protected?
- What’s the risk of not having the scan?
Frequently asked questions
Will my doctor avoid all scans while I’m pregnant?
Not necessarily. They’ll favour radiation-free tests, but a genuinely necessary scan won’t be withheld — because missing an important diagnosis can be the greater risk.[1]
Can I ask for a second opinion on whether I need a scan?
Yes. It’s reasonable to ask why a scan is recommended, what it will change, and whether there’s a radiation-free alternative — that conversation is part of good care.[1]
Sources
- RadiologyInfo.org (RSNA & ACR) — Radiation Dose from X-Ray and CT Exams — www.radiologyinfo.org/en/info/safety-xray
- RANZCR / InsideRadiology — Radiation risk of medical imaging — www.insideradiology.com.au/radiation-risk/
