The strength of X-rays is measured in rads. Rads are the units that show how much radiation
is absorbed by the body. Exposing an unborn baby to more than 10 rads has been shown to increase the risk of learning disabilities and eye problems. But you needn't worry. Most X-rays are much weaker than this. It's rare for any X-ray to be stronger than five rads.
For example, the amount of radiation that your baby would get if you had a dental X-ray is only 0.01 millirad. Since one rad is equal to 1,000 millirads, you would have to have 100,000 dental X-rays for your baby to receive just one rad. Here are the figures for other typical X-rays:
60 millirads for a chest X-ray
290 millirads for an abdominal X-ray
800 millirads for a computerised tomographic (CT) scan (although it’s very unlikely you will be offered one of these if you are pregnant)
To keep it in perspective, during pregnancy
your baby is exposed to about 100 millirads of natural radiation from the sun and earth.
Although the risk from X-rays is low, it is advisable to postpone getting unnecessary X-rays until after your baby is born. However, if it is inevitable, The amount of radiation your baby will receive is likely to be well within the safe range. On the day of the test, make sure the radiographer knows that you are pregnant so she can properly shield you.