Have a baseline mammogram at age 35, then every other year during your forties and every year beginning at age 50. If you have a family history of breast cancer, begin yearly mammograms at age 40. If you are taking estrogen replacement, have yearly mammograms. If you are under 30 and need an evaluation of your breast, ask for a sonogram instead of a mammogram because it will be more accurate. Almost all lumps in breasts before the age of 30 are cysts or fibroadenomas.
Cysts resolve by themselves, but fibroadenomas continue to grow.
If the lump doesn't resolve within two months, see a doctor. Rather than checking your breasts in the shower or when undressed, wear a thin or silky material and feel the breast through the cloth. Slide the fingers of the opposite hand from the outer edge of the breast to the nipple, pretending the fingers are the hands of a clock. It makes lumps much easier to feel. Wear a bra with good support when jumping or running to prevent bouncing.