The primary function of breasts is to produce milk following the birth of a baby (lactation). Each breast is made up of 15-20 lobes. These contain the milk producing glands and ducts along which the milk travels to the nipple. Fat and fibrous tissue surrounds these structures and gives the breasts their individual size and shape. Breasts come in different shapes and sizes and it is normal for one breast to be slightly larger than the other. The size of the breasts does not determine how much milk they will produce. The breasts also contain blood vessels, lymph glands and nerves. Breast tissue is sensitive to touch and can provide sexual pleasure for you and your partner.
Normal breast changes during life
From adolescence to menopause, breast tissue is subject to the hormone changes associated with the menstrual cycle, pregnancy and lactation. Breast tissue can become more tender and lumpy just prior to a menstrual period and less tender and lumpy after a period.
It is normal and quite common for breasts to be lumpy or have benign (non-cancerous) nodules.
In the perimenopausal years, when women transition from regular periods to their final period (menopause), women often experience increased breast discomfort because of a change in hormone levels, which affects breast tissue.
After menopause, the glandular tissue of the breast is largely replaced by fatty tissue.
When to see your doctor
It is important to know your own breasts so you can tell if any changes occur.
You should see your doctor about:
- new lumps
- new lumpiness
- changes in the shape of your breast
- changes in the colour of your breast
- changes in the nipple
- discharge from your nipple
- any persistent breast pain
Last updated 11 October 2017 — Last reviewed 30 January 2014
This web page is designed to be informative and educational. It is not intended to provide specific medical advice or replace advice from your health practitioner. The information above is based on current medical knowledge, evidence and practice as at January 2014.