Wear a two piece outfit. Do not use deodorant, perfume, lotion, or powder on underarms or breasts on the day of your exam as this can show on the images and appear as an abnormality.
Bring previous mammograms with you so that your new films can be compared to the older examinations. Comparing current studies to previous films decreases the number of additional views and callbacks for additional imaging.
It is preferable to have a mammogram within the first two weeks after a period.

General Contraindications:
Screening mammography should be avoided during pregnancy if asymptomatic.
Also, you should wait up to 6 months after cessation of breast feeding before your mammogram.