Answer to Question #11725 Submitted to "Ask the Experts"

Category: Pregnancy and Radiation — Power lines, magnets, computers, airport screening, cell phones, radar

The following question was answered by an expert in the appropriate field:


I am working with a magnetic resonance imaging (MRI) magnet. The magnetic field is 4.7 teslas (T). We are planning to have a baby. My questions are:

  • Does the magnetic field have any effect on fertility?
  • Is the magnetic field harmful during pregnancy? If yes, how long before getting pregnant must I avoid it?

Based on currently available information, there should be no effect on the fertilization process or harm during pregnancy.

In most organizations where MRI units are used, the magnet room may have a high magnetic field, but because of the shielding of the room, the magnetic field in the control room and other adjacent areas are well below those levels and are safe for the employees whether pregnant or not. You may have to check with your organization's safety officer or the radiology department's physicist to find out what shielding is in the walls of the MRI room and what the magnetic field levels are in the control area.

There have been studies on workers in MRI areas, one specifically on 280 pregnant workers in an MRI environment, and there were no increases in health effects for the baby (Kanal et al. 1993). A more recent study looked at outcomes of pregnant patients who underwent an MRI, and there also was no increase in health effects due to having an MRI while pregnant (Choi et al. 2015).

Another study looked at pregnant mice exposed to strong magnetic fields (up to 7 T) for 45 minutes daily during the course of the pregnancy. This study found no general health effects, although there was a delay in how quickly the babies gained weight and when they first opened their eyes (Zahedi et al. 2014).

It should be safe for you to continue working in the MRI environment.

Kelly Classic
Certified Medical Health Physicist


Choi JS, Ahn HK, Han JY, Han YJ, Kwak DO, Velazquez-Armenta EY, Nava-Ocamp AA. A case series of 15 women inadvertently exposed to magnetic resonance imaging in the first trimester of pregnancy. J Obstet Gynaecol 35(8):871–2; 2015.

Kanal E, Gillen J, Evans A, Savitz DA, Shellock FG. Survey of reproductive health among female MR workers. Radiology 187:395–399; 1993.

Zahedi Y, Zaun G, Maderwald S, Orzada S, Putter C, Scherag A, Winterhager E, Ladd ME, Grummer R. Impact of repetitive exposure to strong static magnetic fields on pregnancy and embryonic development of mice. Magn Reson Imaging 39(3):691–9; March 2014.

Ask the Experts is posting answers using only SI (the International System of Units) in accordance with international practice. To convert these to traditional units we have prepared a conversion table. You can also view a diagram to help put the radiation information presented in this question and answer in perspective. Explanations of radiation terms can be found here.
Answer posted on 18 September 2016. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.