Hormones are proteins in the body that act as chemical messengers and control many bodily functions. The female reproductive hormones include estrogen and progesterone. Fluctuations in the levels of these two hormones often cause breast pain in many women.

One of the most common hormonal changes to cause breast pain occurs during menstruation. Menstruation is the period in which nonpregnant women discharge blood from their uterus. Often referred to as a woman’s monthly period, menstruation occurs approximately every 28 days from puberty to menopause (the period that marks the end of menstruation). During menstruation, it is fairly common for women to retain water in their bodies. The additional water can cause pressure within the breast tissue, which leads to pain or tenderness in the breasts.

Menstruation is also linked to fibrocystic breast changes, a common cause of breast pain in women. Fibrocystic changes, which typically affect women approaching middle age and often disappear during menopause, are characterized as lumpy, tender breasts. These benign (noncancerous) changes are often found around or near the nipple or upper, outer portion of the breast.

Another possible cause of breast pain in women of reproductive age is the use of oral contraceptives (birth control pills). Many women choose to take birth control pills in order to avoid unplanned pregnancy. This method of contraception alters a woman’s cyclical hormone levels. Common side effects of oral contraceptives can include breast tenderness, pain and discharge.

Although most breast pain is reported in premenopausal women, it can affect women nearing menopause and postmenopausal women. For instance, a condition called mammary duct ectasia, which occurs when the ducts beneath the nipple become clogged, can cause breast pain in women who are approaching menopause. Once diagnosed, the condition can be treated with warm compresses, antibiotics or possibly surgery. In addition, a significant portion of postmenopausal women who take hormone replacement therapy (HRT) also experience breast tenderness or pain. Postmenopausal women who experience breast pain while taking HRT also may be forming denser breast tissue and increasing their risk of breast cancer, according to a recent study.

Other hormonal changes commonly associated with breast pain include puberty (in both girls and boys), pregnancy and breastfeeding.