Answer to Question #12941 Submitted to "Ask the Experts"
The following question was answered by an expert in the appropriate field:
Last week my girlfriend received an abdominal computerized tomography (CT) scan at 12 weeks of fetus development which is right in the middle of the highest risk period of 8–15 weeks. The test was ordered by her general practitioner because she was complaining of abdominal pain and a distended stomach. I'm looking for recommendations on specific actions to take now to assess the risk and locate the right resources.
Is a maternal fetal medicine specialist someone who specializes in radiology? We want to locate the best possible resource.
It is highly unlikely that the low radiation dose received from the CT scan will cause harmful effects for the fetus.
The radiation dose to the fetus from an abdominal CT procedure will vary depending on the equipment, scanning parameters used, and patient size. An average dose would be around 4 milligray (mGy—a unit of radiation absorbed dose) with and without contrast. The publications I've listed below will give you more detail on the doses.
The radiation dose necessary to cause fetal harm ranges from 100 mGy and upward between weeks 8 and 15. The radiation dose received by your girlfriend was much lower than this (by a factor of 25) and not expected to cause harmful effects.
Most diagnostic procedures that expose the abdomen or pelvis to radiation when you are pregnant will not harm the fetus. The radiation doses are too low.
As for your question about a maternal fetal medicine specialist, I doubt they would know much about radiation, radiation doses, and effects on pregnancy. The person at a hospital who often knows the most about radiation effects is a radiologist (diagnostic radiation specialist) or radiation oncologist (radiation therapy cancer specialist) or a nuclear medicine physician (radiopharmaceutical use specialist).
Certified Medical Health Physicist
Publications that may be of interest:
- Hall EJ and Giaccia AJ. Radiobiology for the radiologist. 6th Ed. Lippincott Williams & Wilkins, New York. 2006.
- Mettler FA and Upton AC. Medical effects of ionizing radiation. 6th Ed. London: WB Saunders Company; 1995.
- McCollough CH, Schueler BA, Atwell TD, Braun NN, Regner DM, Brown DL, LeRoy AJ. Radiation exposure and pregnancy: when should we be concerned? Radiographics 27(4):2007. Available at https://www.ncbi.nlm.nih.gov/pubmed/17620458/. Accessed 19 May 2019.
- Nikolic B, Spies JB, Lunsten MJ, Abbara S. Patient radiation dose associated with uterine artery embolization. Med Phys: January 2000.