As a girl approaches her teen years, the first visible signs of breast development begin. When the ovaries start to produce and release (secrete) estrogen, fat in the connective tissue starts to collect. This causes the breasts to enlarge.
The hormone estrogen, if taken in high enough doses, increases breast size by stimulating growth of breast tissue. However, it is not safe to use estrogen in this way because when breast cells are stimulated to grow, they are more likely to turn cancerous.
Gigantomastia or breast hypertrophy is a rare condition that involves developing extremely large breasts due to excessive breast tissue growth. It affects people assigned female at birth. If you have gigantomastia, you'll experience rapid and disproportionate breast growth.
Next, a drop in oestrogen levels causes breasts to undergo a process known as "involution", where your milk glands shut down, and the tissue is replaced by fat. Weight distribution, with excess fat tissue moving from other parts of the body into the breasts, may also cause breast enlargement.
In models for current users, large breast sizes were significantly associated with high prolactin and luteinizing hormone levels and low follicle-stimulating hormone levels during cycle days 5-10. During cycle days 18-23, larger breast sizes correlated with low endogenous progesterone levels.
As estrogen levels decrease, your breast tissue changes. The tissue in your breasts gets dehydrated and isn't as elastic as it used to be. This can lead to a loss of volume, and your breasts may shrink as much as a cup size.
As you reach the age of 40 years and approach perimenopause, hormonal changes will cause changes to your breasts. Besides noting changes in your breasts' size, shape, and elasticity, you might also notice more bumps and lumps. Aging comes with an increased risk of breast cancer.
It has been previously suggested that female breast morphology arose as a result of sexual selection. This is supported by evidence showing that women with larger breasts tend to have higher estrogen levels; breast size may therefore serve as an indicator of potential fertility.
As females get older, their bodies start to produce less of the reproductive hormone estrogen than before. Estrogen stimulates the growth of breast tissue, while low levels of this hormone cause the mammary glands to shrink.
Hormone Changes and Your Breasts
Menstrual cycles: Increased production of estrogen early in the menstrual cycle causes breast swelling and tenderness in many women as the breast ducts become larger. Having a high-fat diet and taking in a lot of caffeine can also contribute to breast swelling.
Breasts are very responsive to hormones in the menstrual cycle or in HRT. Hormones called oestrogens increase before a period, causing milk ducts and glands to swell. This can trap fluid in the breasts and cause swelling and lumpiness.
Genetics: Some men and women are predisposed to having a fuller breast size. This can be inherited from both the mother's and father's side of the family. Hormonal Changes: Women develop their breasts during puberty as estrogen increases.
During perimenopause, the hormonal fluctuations are more dramatic. It is also common for breasts to get bigger or smaller or to change in shape during this period.
"During perimenopause and menopause, there are hormonal fluctuations and eventually a drop in hormones that may cause weight gain," said Dr. Wider. "As a result, some of the weight gain can occur in the breasts, resulting in enlarged breasts."
As oestrogen goes AWOL, breasts go through a process called 'involution' where milk glands shut down and this tissue is replaced by fat. Weight gain also causes an accumulation of fat cells, and some of these camps out in your bra.
Physical Changes in Your Breasts
In the hormone's absence, the breasts shrink because the ducts and mammary glands shrink, and the breasts become less firm and lose their shape. You may notice a sagging of the breasts in older women.
Breast development occurs in stages, beginning before birth, changing during puberty and the childbearing years, and ending at menopause. Breasts can grow in response to hormones estrogen and progesterone, as well as pathological conditions such as benign and cancerous breast tumors and certain medications.