X-rays, CT and MRI During Pregnancy: Imaging Safety

How ultrasound, MRI, X-rays and CT differ

Two examinations with the same general name may use different protocols and result in different fetal doses. The word “radiology” does not mean every examination has the same exposure or risk.

Does an X-ray mean my baby has been harmed?

Having an X-ray during pregnancy does not establish that the baby has been harmed. The important details include the body area, technique, pregnancy week and estimated fetal radiation dose, rather than simply the number of images.

During imaging of the head, limbs or chest, the fetus is generally outside the direct beam. Abdominal and pelvic examinations require their own assessment. The risk of leaving a serious maternal illness undiagnosed also matters.

The radiology team selects the examination and protocol that can answer the clinical question. If imaging has already taken place, request the examination report and any available dose information for an individual review.

Why might urgent imaging go ahead?

Delaying the diagnosis of major trauma, a suspected blood clot in the lungs or a serious abdominal condition may put both the mother and baby at risk. If ultrasound or MRI cannot provide the necessary answer, CT may be the appropriate examination.

Tell the referring and radiology teams that you are pregnant or could be pregnant. Ask what they need to investigate and how the result will change treatment. A single dose figure found online should not replace this discussion or lead you to refuse necessary emergency care.

I had an X-ray or CT before I knew I was pregnant

This does not by itself mean the pregnancy needs to be ended. Record the date, body area, number and type of examinations, whether contrast was used and the estimated pregnancy week at the time.

Ask for the radiology report and dose record if available. A radiologist and, when needed, a medical physicist can estimate fetal exposure. A scan directly involving the abdomen or pelvis is assessed differently from an examination of a distant body area.

Discuss the actual exposure with your obstetrician. The need for further counselling or follow-up is based on those details, rather than the general statement that an X-ray was performed.

What about contrast material?

Iodinated contrast used with CT and gadolinium used with MRI are different substances. Gadolinium is not routinely used during pregnancy; its potential diagnostic benefit and risks require specific consideration. Iodinated contrast is also used only when it is needed.

Tell the team about previous contrast reactions, kidney disease and thyroid conditions. MRI not using ionising radiation does not mean every MRI protocol or contrast injection is automatically appropriate.

What information should I bring?

Bring the exact examination name, the reason for the referral, the planned or actual date, your last menstrual period and previous imaging reports. “Chest X-ray”, “dental X-ray” or “abdominal CT” is more useful than “I had a scan”.

Previous images may prevent unnecessary repetition. A routine pregnancy ultrasound cannot replace every type of imaging needed to investigate a mother’s illness.

Common questions

Can I have a dental X-ray while pregnant?

Dental X-rays may be used when needed for diagnosis or treatment. Tell the dentist that you are pregnant and your pregnancy week. Necessary dental care should not be postponed simply because of pregnancy. A small dental film, panoramic image and dental CT are different examinations.

Does radiation stay in my body after an X-ray?

No. X-rays do not leave radiation in the body after the examination. Assessment concerns exposure during the test. Nuclear medicine examinations that use radioactive tracers are different; tell your team the exact test name.

Does a dental X-ray have the same risk as an abdominal CT?

No. The imaging area, technique and fetal dose are different. Risk is assessed from the details of the actual examination.

Can MRI be used during pregnancy?

MRI may be considered when medically necessary. It does not use ionising radiation. Any need for contrast material is assessed separately.

Should I arrange extra tests immediately after accidental exposure?

First establish what exposure occurred. The examination details and pregnancy information determine whether additional counselling or follow-up is appropriate.