Pregnancy and Fetal Safety FAQ

What should be done if I am pregnant and I need a medical imaging procedure?

Be sure that the medical radiation procedure is necessary and that the benefit outweighs the risk to both you and the fetus. You have a right to know the estimated radiation dose and potential effects that might result from in-utero exposure. Communication between you and the radiology team is based on the level of risk. The radiology team will routinely consider techniques and procedures that reduce the radiation dose while still obtaining the required information. When the fetus is directly exposed during a procedure and the dose is greater than 1 mSv, then a patient specific fetal dose calculation by a qualified medical physicist may be provided to the patient's obstetrician.

Should I be worried about having a CT scan during pregnancy?

Imaging procedures that directly expose the fetus to radiation (such as CT of the abdomen or pelvis) may require prior approval by a radiologist. A fetal radiation dose calculation by a qualified medical physicist may be provided after the scan. Radiologists and technologists work together to minimize the radiation dose to the fetus. This includes using alternate imaging modalities (such as MRI and ultrasound) and other imaging systems that may expose the fetus to a lower dose.

Many CT scans do not directly expose the developing fetus to radiation, such as:

  • Head CT
  • Neck CT (cervical or thoracic spine CT)
  • Chest CT (Routine Chest, Chest PE, Heart scan, Chest CTA)
  • Extremity CT (knees, legs, shoulder)

Should radiologists specifically approve head, neck, chest and extremity CT scans during pregnancy?

No. Scans that do not include the abdomen or pelvis give very little radiation to the developing fetus. Fetal radiation exposure is highest in areas that go through the CT opening during the scan. The x-rays come out of the circular opening in a small, thin beam and pass through to the other side to make the image. If the fetus is outside the area exposed, then it will get very little radiation.

There is some scatter radiation, which are x-rays that deflect off tissue in your body and bounce through the body. These scatter x-rays can make it to the fetus, but there are not very many of them. The amount of scatter exposing the fetus depends on how close the fetus is to the scan region.

Should I have a shield over my abdomen during the scan?

No, using a lead apron over the abdomen during the scan of another body region does very little to reduce scatter radiation. This is because most of the scatter dose is deflected inside your body, and does not encounter the shield. A lead apron CANNOT be used for abdomen scans, because it renders the images unreadable by the radiologist.

Will I be radioactive after the scan and hurt my fetus?

No, once the scanner is off, the radiation dose to you and your fetus stops.

I am waiting in the room directly next to the CT scanner. Should I be worried about radiation exposure to my fetus while I am waiting?

No, the radiation dose in waiting rooms, corridors, and areas immediately adjacent to the CT scan room are protected with structural lead shielding that limits the radiation to background levels.

I am still concerned. How do I know the dose my fetus gets from my CT scan if no one calculates it?

A patient specific fetal radiation dose calculation may be provided for fetuses that receive direct CT exposure. CT scans that do not include the abdomen or pelvis give very little radiation. To put this in perspective, each person is exposed to natural background radiation, and this cannot be avoided easily. While you are carrying your fetus to term, it is also exposed to background radiation (BKG), which is about 2.3 mSv over 9 months. These are the estimated fetal doses for CT scans that do not directly expose the fetus.

  • Chest CT less than 1 mSv less than 4 months BKG
  • Heart CT less than 0.06 mSv less than 10 days BKG
  • Head, neck CT less than 0.005 mSv less than 1 day BKG

If I am breast feeding, what precautions should I take?

Nursing mothers should wait for 24 hours after contrast material injection before resuming breast-feeding. In nuclear medicine, sometimes the radioactive tracer (called radiopharmaceutical) used for the study may pass into the mother's milk and subsequently the child will consume them. To avoid this possibility, it is important for the nursing mother to inform her physician and the nuclear medicine technologist about this before the examination begins. Usually, you will be asked to discontinue breast-feeding for a short while, pump your breasts in the interim and discard the milk. Breast-feeding can often resume shortly afterwards.