Radiation exposure during pregnancy

Radiation is a type of energy that travels in waves or tiny particles. People are exposed to radiation from different natural and artificial sources in the environment every day. This is called 'background radiation'.

'Ionising radiation' refers to radiation that can make changes to body cells.

In Australia, people usually get about 2 millisieverts (mSv) of background radiation every year.

Medical procedures that use radiation include:

• x-rays
• CT scans
• mammography
• fluoroscopy
• nuclear medicine
• angiography

A chest x-ray exposes you to up to 0.1 mSv and a CT scan exposes you to up to 8mSV of ionising radiation. The exposure depends on the body part and type of imaging required.

If you're pregnant or thinking about becoming pregnant, tell your doctor and the radiology practice before you have any tests. You can discuss whether the test is necessary.

Tests that don't use ionising radiation, such as magnetic resonance imaging (MRI) or ultrasound, may be useful alternatives in some situations.

Most radiation exposure during medical testing is unlikely to harm your developing baby. Sometimes the effects can be serious and may result in:

• miscarriage
• changes to the way your baby's organs form
• learning problems or developmental disability
• slower growth
• childhood cancer

Any harm to your developing baby will depend on:

• the radiation dose — smaller doses (amounts) are safer
• the stage of your pregnancy — the further along you are in your pregnancy, the better
• where in your body the radiation is given — tests involving your abdomen (tummy) or pelvis have a higher risk than other tests

Here is a summary of some of the potential health effects that radiation could have on your baby during pregnancy:

Chart explaining how certain levels of radiation can effect your pregnancy at different stages.

Stage of your pregnancy	Radiation level	Possible effect that level of radiation may have on your pregnancy
Up 2 weeks pregnancy	50 to 100mSV	Your embryo is not likely to implant in your uterus. If it does, your baby will probably have health issues.
2 to 8 weeks of pregnancy	200 to 250 mSV	Your baby may not grow as much as expected. The baby might have major differences.
8 to 15 weeks of pregnancy	60 to 310 mSV	Your baby is at risk of having problems with brain development.
16 to 25 weeks of pregnancy	250 to 280 mSv	Your baby is at risk of being born with severe intellectual disability.

If you are accidentally exposed to radiation from medical imaging while you're pregnant, you should talk to your doctor as soon as possible.

They can work out the dose of radiation to your baby and check if you are at risk. Often a single exposure to a low dose of radiation (for example, an x-ray) is not likely to be harmful to your baby.

If you are pregnant or planning to become pregnant, and your work exposes you to radiation, it is important to talk to your employer about how you can be protected.

Read more on workplace exposure to radiation for pregnant workers at the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) website.

If you are exposed to radiation in an emergency, you should follow instructions from emergency officials and seek medical attention as soon as possible.

Usually, your baby will receive less radiation than you. Your abdomen (tummy) partially protects your baby.

If you swallow or breathe in radiation, it can reach your baby.

Radioactive material can be passed to babies through breast milk. If you have had a nuclear medicine scan, be sure to check with your health team before breastfeeding your baby. Your doctor will assess the risks of exposing your baby to radiation against your health needs. They will advise you on when to stop breastfeeding.

You can feed your baby stored breast milk that you expressed before being exposed to radiation.

Speak to your doctor or health professional about when to start safely breastfeeding again.

Radiotherapy, or radiation therapy, is a treatment for some cancers.

You may be advised to have radiotherapy as a treatment for cancer during your pregnancy. If you're in this situation, you and your doctor can weigh up the benefits of the radiotherapy against any potential harm to your developing baby.

If you think you may be pregnant at any stage of radiotherapy, you should discuss with your doctor whether to continue the treatment.

If you are having radiotherapy while breastfeeding, ask your health team for advice.

Speak to your doctor and the medical imaging technologist if you are pregnant and need a scan or test that might involve radiation.

Read more on medical imaging in pregnancy by visiting the Agency for Clinical Innovation.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with 24 hours a day, 7 days a week.

Information for Aboriginal and/or Torres Strait Islander peoples

Read more about radiation therapy for Aboriginal and/or Torres Strait Islander people at Cancer Council NSW's Aboriginal and Torres Strait Islander Cancer Website.

Learn more about Aboriginal and/or Torres Strait Islander pregnancy health at Stronger Bubba Born.