What is radiation?

If you’re pregnant or thinking about becoming pregnant, you might be worried about x-rays and other forms of radiation. It's important you discuss any concerns with your doctor and always tell a health professional that you are pregnant before you have any medical imaging.

Radiation is energy that travels through air, and some materials, as waves or tiny particles. We are exposed daily to radiation from different natural and artificial sources, such as the sun, microwaves and radio waves.

The type of radiation used in medical imaging is called ionising radiation. In Australia, people receive about 1,500 to 2,000 μSv of ionising radiation every year from natural sources. This level of radiation is not harmful.

A typical x-ray or CT scan of exposes you to 2,600 μSv of ionising radiation.

X-rays and some other forms of radiation can alter the molecules that make up the body. At high enough doses, radiation can kill cells and damage genes.

Medical procedures that give off radiation

If you are pregnant or think you might be pregnant, you should be cautious about medical procedures that use radiation, such as:

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

Tell your doctor and tell the radiology practice before you have any tests. You can discuss whether they can be delayed or avoided, and whether there are alternative tests.

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

What are the effects of radiation on a mother and unborn baby?

Any harm to the developing baby will depend on:

• the radiation dose – smaller doses (amounts) are safer
• the age of the fetus – the further along you are in your pregnancy, the better
• where the radiation is administered – tests involving your abdomen or pelvis, or where the radiation is carried in your blood, pose a higher risk than other tests

Most radiation exposure during medical testing is unlikely to harm a developing baby. But sometimes, depending on the radiation dose and the developmental stage of the fetus, the effects can be serious and may result in:

• failure of the embryo to implant
• miscarriage
• abnormalities of the central nervous system
• congenital malformations
• slower than normal growth
• malformation
• cataracts
• childhood cancer

Accidental exposure to radiation

If you are accidently exposed to radiation from medical imaging while you are pregnant, you should talk to your doctor. The risk to your baby can be worked out using a formula and should be calculated by an expert. Most normal doses or a single exposure to radiation are not likely to be harmful to the baby.

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, the fetus receives less radiation than the mother. The mother’s abdomen partially protects the baby. However, if you swallow or breathe in radiation, it can cross over into the baby. The baby is most sensitive to radiation from 2 to 18 weeks of pregnancy.

If you are exposed to radiation while you are breastfeeding, you should feed your baby with pre-pumped and stored breast milk or formula, if possible. If there is no other source of food available to feed your baby, then continue to breastfeed, but wipe the breast and nipple thoroughly with soap and water before feeding.

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

Radiotherapy for cancer

Radiotherapy, or radiation therapy, is a treatment for some sorts of cancers. Sometimes a pregnant woman is advised to have radiotherapy as a treatment for cancer during 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 suspect you may be pregnant at any stage of radiotherapy, you should discuss with your doctor whether to continue the treatment.

Radioactive material can be passed to babies through breast milk. Breastfeeding mothers undergoing radiotherapy should ask a health professional for advice.

Radiation, pregnancy and the workplace

If you are pregnant or planning to become pregnant, and your work exposes you to radiation, it is important to discuss alternative roles with your employer.

Speak to a healthcare professional if you are worried about radiotherapy exposure during pregnancy.