Your breasts may go through a variety of healthy changes throughout your lifetime.
Several months before the onset of menstruation, female hormones signal the body to begin developing breasts. Breasts may feel tender or even hurt a little at this time. One breast may develop more quickly than the other so there may be a slight size difference.
Many women’s breasts feel tender around the time of their period. The tenderness is due to female hormones, primarily estrogen, which cause the mammary glands to swell. The swelling and tenderness usually lessens or disappears after your period. If your breasts get tender around the time of your period, schedule your mammogram for one week after your period ends.
Like other parts of your body that contain fatty tissue, your breasts may change in size or shape if you lose or gain weight.
Breasts usually enlarge during pregnancy as mammary glands prepare for milk production. Breasts remain larger until breastfeeding stops. Breasts may become tender early in pregnancy and remain sensitive until childbirth. Leakage of a clear or whitish fluid is also a normal breast change during pregnancy.
Mammary glands and ducts begin decreasing in size at menopause. This is also a time when fibrous tissue thins and is replaced by softer, fatty tissue.
Birth Control Pills and Hormone Replacement Therapy
The use of birth control pills or hormone replacement therapy may result in breasts feeling tender and swelling slightly.