If you need to have a mammogram, or any kind of x-ray or scan while you’re pregnant, there’s a good chance that you will be concerned about the possible negative effects on your baby. However, the effects of radiation do depend largely on the gestational age of your baby, and a variety of other factors, and the amounts of radiation present in a single mammogram scan are generally not considered enough to cause any lasting harm to your baby.
If, however, you need to have more than one scan or x-ray, you should bear in mind that the effects of radiation are cumulative, and that repeated exposure to radiation can harm your child. This could include mental retardation, growth restriction, and an increased risk of cancer.
The best bet, if you need to have a mammogram (or any other kind of scan) while you’re pregnant, is to double check with your doctor first. Remember that your own health is also important to your baby!