Wednesday, October 29, 2008

Breast Size and Functions

Breasts go through a number of changes during pregnancy. These changes include:

  • Breasts grow in size and get enlarged.
  • Breasts become tender or soft with hypersensitivity.
  • Hormones affect pigmentation of the skin around the nipples. Darkening of nipples and areolas are common features. Veins along the breasts also become visible as the blood supply to the breasts increases.
  • Breasts may start leaking a yellowish, thick substance known as colostrums.
  • The areolae and nipples will grow larger and the nipples stick out more.
  • Small glands called Montgomery's tubercles on the surface of the areolae will appear as raised bumps.


Women will experience a change in breast size and that could be the first hint that they are pregnant. Even before the pregnancy is confirmed, women may notice an increase in size and perhaps some softness also.

The hormone progesterone increases the size of the alveoli, the milk producing units of the breast. The milk is secreted from the blood that flow in the lobes. The lobes, which are sections of the alveoli and connecting ducts, permit the milk to flow from the alveoli in to the openings of the nipple.


You can visualize a bunch of grapes and compare with the structure of the alveoli and the connecting ducts. The alveoli may be represented by the grapes; the ducts could be represented by the stems. The lobes could be an entire bunch of grapes with the top of the stem as a duct ending at the nipple.


The milk is made from the blood stream in the alveoli (grape) and that moves down through the ducts (stems).The milk moves from the smallest duct to the largest ending at a small pouch under the areola, called the lactiferous sinus.

The hormone estrogen promotes the growth of breasts during pregnancy by branching ductile system. Besides breast growth, prolactin and other hormones also contribute to the preparation for breast feeding.


Women may observe a darker skin color around the nipple, the areola, and increase in diameter. It is believed that the darker color of the nipple and areola helps the newborn to identify the spot of the nipple.

The Montgomery glands which look like pimples on the areola enlarge during pregnancy. They secrete a substance that lubricates and helps to protect the areolae from infection. Women should not use soap or any preparation that toughens of the nipples, since this may interfere with the effectiveness of the Montgomery glands.


During the third month of pregnancy the Colostrum begins to appear. Colostrum is the first thick yellow nutrient-rich milk an immune component that the breast will produce for the baby's first few days.

Some women may notice slight drainage of Colostrum from their nipples with a small amount of blood also occasionally. This is not a reason for concern. Due to the rapid growth of blood vessels in the growing ductal system, drops of blood may leak along with the milk.


The Colostrum may temporarily stick to the nipple to the inside of the bra; a tiny bit of nipple skin may get removed with the bra. Understandably, this could also cause alarm in the pregnant mother.


In the last three months the breast continues to expand liberally from the enlargement of milk making cells and distention with Colostrum. The growing breast size and shape with the change in areola and nipple may have a say in wearing kind of blouses and night wears for comfort and milk feeding.

She may need an open loose blouse, feeding bra and feeding gown or night wear for comfort and convenience of feeding the child.