Radiation and pregnancy

The risks to pregnancy from exposure to ionising radiation are very small, and in most cases avoidable. We are all subject to natural ‘background’ radiation, and this is nothing to worry about. You are most likely to be exposed to additional ionising radiation during medical procedures, but medical staff take care to avoid exposing pregnant women, or women who might be pregnant, wherever possible.

Types of radiation

It is important to know that an ultrasound, which is used in antenatal screening and testing, does not use ionising radiation. Neither do MRI scans which are a type of scan often used to diagnose health conditions that affect organs, tissue and bone.

Ionising radiation is used in x-rays, CT scans and nuclear medicine during procedures to diagnose certain medical conditions. It is the job of radiation professionals (radiologists and radiographers) to ensure that patients are only irradiated when the benefits of making a diagnosis outweigh the small risk from the radiation, and particular care is taken to avoid the exposure of women who are, or might be, pregnant.

At the low dose levels used in diagnosis, the only adverse effect is an increase in the risk of malignant disease (cancer) occurring during childhood. The ‘natural’ risk of childhood cancer (i.e. for a child not exposed before they are born) is about 1 in 500.

Some women worry about the x-ray scanners (hand-held and whole body) used for security screening in some airports. The radiation dose from these is tiny – equivalent to that received every few minutes from background radiation, and it only penetrates a few millimetres into your body. However, if you are worried, you can request a body search instead.

Ionising radiation during pregnancy

There are two situations in which you might possibly be subjected to medical irradiation while pregnant:

You didn’t know you were pregnant

You may have an examination involving ionising radiation, and only discover later that you were in the early stages of pregnancy at the time. Great care is taken to avoid this, but sometimes patients just aren’t aware of the pregnancy at the time of their x-ray or scan. 

If this happens you will naturally be worried about the effects of the radiation on your unborn child. The good news is that even for the highest dose procedures likely to be carried out in hospitals, the absolute risk to the foetus is very small indeed. 

When the benefits of using radiation outweigh the risks

In some situations, you may know you are pregnant, but a deliberate decision will be taken to go ahead with a procedure using ionising radiation. This will only happen if the doctors treating you feel that the risk to your health and that of your unborn child of not doing the scan (and thereby delaying diagnosis and treatment) is greater than the risk from the radiation. This is a much less common scenario than the previous one, and the doctors will involve you in the decision and make sure that you understand the relative risks involved.

Further information

You can find more information about the relative risks and benefits of the diagnostic use of radiation on the Health Protection Agency website.

NHS Choices gives information on radiation and having an X-ray when pregnant. 

NCT's helpline offers practical and emotional support in all areas of pregnancy, birth and early parenthood: 0300 330 0700.  We also offer antenatal courses which are a great way to find out more about birth, labour and life with a new baby.