NORMAL BREAST DEVELOPMENT
What is normal
development is a vital part of reproduction in the human
female. Unlike other mammals, however, human females are the
only ones who develop full breasts long before they are
needed to nurse their offspring.
development occurs in distinct stages throughout a woman's
life, first before birth, and again at puberty and during
the childbearing years. Changes also occur to the breasts
during menstruation and when a woman reaches menopause.
development and kinds of breast changes that take place are
directly related to age. There are three phases of
development: lobule development, which takes place between
the ages of 10 and 25; glandular development, which is under
the influence of menstrual hormones and occurs between the
ages of about 13 and 45, and involution, or shrinkage of the
milk ducts, which begins from about age 35 on.
When does breast development begin?
stage of development begins at about six weeks of fetal
development with a thickening called the mammary ridge or
the milk line. By six months of development this extends all
the way down to the groin, but then regresses. At this time,
solid columns of cells form from each breast bud, with each
column becoming a separate sweat gland. Each of these has
its own separate duct leading to the nipple. By the final
months of fetal development, these columns have become
hollow, and by the time a female infant is born, a nipple
and the beginnings of the milk-duct system have formed.
What breast changes happen at puberty?
As a girl approaches adolescence,
the first outward signs of breast development begin to
appear. When the ovaries start to secrete estrogen, fat in
the connective tissue begins to accumulate causing the
breasts to enlarge. The duct system also begins to grow.
Usually the onset of these breast changes is also
accompanied by the appearance of pubic hair and hair under
ovulation and menstruation begin, the maturing of the
breasts begins with the formation of secretory glands at the
end of the milk ducts. The breasts and duct system continue
to grow and mature, with the development of many glands and
lobules. The rate at which breasts grow varies greatly and
is different for each young woman.
Female Breast Developmental Stages
(Preadolescent) only the tip of the nipple
appear, breast and nipple raised, and the areola
(dark area of skin that surrounds the nipple)
breasts are slightly larger with glandular breast
areola and nipple become raised and form a second
mound above the rest of the breast
mature adult breast; the breast becomes rounded and
only the nipple is raised
Five Stages of
Breasts during childhood
are flat and show no signs of development
2. Breast bud
Milk ducts and
fat tissue form a small mound
continue to grow
rounder and fuller
4. Nipple and
areola form separate small mound.
Not all girls
go through this stage
stage 4 and go directly to stage 5
growth enters finial stage
is full and round shaped
changes occur to the breasts during menstruation?
month, women experience fluctuations in hormones that make
up the normal menstrual cycle. Estrogen, which is produced
by the ovaries in the first half of the menstrual cycle,
stimulates the growth of milk ducts in the breasts. The
increasing level of estrogen leads to ovulation halfway
through the cycle, and then the hormone progesterone takes
over in the second half of the cycle, stimulating the
formation of the milk glands. These hormones are believed to
be responsible for the cyclical changes such as the
swelling, pain, and tenderness that many women experience in
their breasts just before menstruation.
During menstruation, many women also experience changes in
breast texture, with breasts feeling particularly lumpy.
These are the glands in the breast enlarging to prepare for
a possible pregnancy. If pregnancy does not occur, the
breasts return to normal size. Once menstruation begins, the
cycle begins again.
What happens to the breasts
during pregnancy and lactation?
physicians believe the breasts are not fully mature until a
woman has given birth and produced milk. Breast changes are
one of the earliest signs of pregnancy - a result of the
pregnancy hormone, progesterone. In addition, the areolas
(the dark areas of skin that surround the nipples of the
breasts) begin to swell followed by the rapid swelling of
the breasts themselves. Most pregnant women experience
tenderness down the sides of the breasts and tingling or
soreness of the nipples because of the growth of the milk
duct system and the formation of the many more lobules.
the fifth or sixth month of pregnancy, the breasts are fully
capable of producing milk. As in puberty, estrogen controls
the growth of the ducts and progesterone controls the growth
of the glandular buds. Many other hormones, such as follicle
stimulating hormone (FSH), luteinizing hormone (LH),
prolactin, oxytocin, and human placental lactogen (HPL) also
play vital roles in milk production.
Other physical changes, such as the prominence of the blood
vessels in the breast and the enlargement and darkening of
the areola occur. All of these changes are in preparation
for breastfeeding the baby after birth.
Breasts During Breastfeeding
During breastfeeding, the breasts are larger than before
pregnancy and can appear quite full (they are full of milk).
Of course, after a nursing session the fullness is much
less. In general they are about the same size as during
pregnancy, just varying in fullness according to the baby's
With weaning, the milk glands atrophy or shrink to almost
nothing. This will make the breast look very empty.
Remember, at lot of the fat left the breasts during
pregnancy. After weaning, over the course of several months,
the body will start depositing fat into the breasts again,
and so gradually the breasts will regain their pre-pregnancy
size or close to it.
However, that "fat back to breasts" does not happen to all
women. Some women do end up with empty-looking breasts after
weaning. You can consider it a mark of motherhood! That is,
until the next pregnancy possibly comes along, and the cycle
starts again: the milk glands develop, the ducts grow in
Breast Development During
Breasts grow in size considerably during pregnancy because
of further growth of the milk ducts and milk producing
glands. Teenagers breasts are mostly fat, but during
pregnancy that fat gradually disappears and gives space for
the milk-producing system.
Also the areola enlargens and becomes darker, making a big
contrast with the surrounding skin, as if really pointing
out where the "nutrition center" is. Thus the breasts will
be fully mature and ready for their job, producing milk for
What happens to the breasts
the time a woman reaches her late 40s and early 50s,
menopause is beginning or is well underway. At this time,
the levels of estrogen and progesterone begin to fluctuate,
with levels of estrogen dramatically decreasing. This leads
to many of the symptoms commonly associated with menopause.
With this reduction in the stimulation by estrogen to all
tissues of the body, including the breast tissue, there is a
reduction in the glandular tissue of the breasts. Without
estrogen, the connective tissue of the breast becomes
dehydrated and inelastic, and the breast tissue, which was
prepared to make milk, shrinks and loses shape. This leads
to the "sagging" of the breasts often associated with women
of this age.
Women who are on hormone replacement therapy may experience
some of the premenstrual breast symptoms that they
experienced while they were still menstruating, which can
even include tenderness and swelling. However, if there was
sagging of the breasts before menopause, this is not
reversed with hormone
menopause, the milk producing system â€“ ducts and milk
glands â€“ shrink, and are replaced by fat (just like after
weaning). That makes the breasts softer. Also the connective
tissue loses strength, which makes the breasts sag more.
Teens Worry If Their Breasts
the following comments sent to this website show, teenagers
do worry a lot about their breast size/shape/development,
and many teen girls wish for bigger breasts:
Breast size is determined by your genes. You can look to
your mom and other female relatives and get somewhat of an
idea of what your breast size might end up being, though
this is NOT a guarantee.
Another factor in breast size is how skinny/fat you are. As
mentioned already, breasts have a lot of fat in them. The
skinnier you are, the less fat your breasts contain and
smaller they are. When you gain weight (or fat) in general,
some of that fat will get deposited in your breasts, so that
is why obese people will have bigger breasts. And if you
lose weight (fat) from your body, some of that fat will be
lost from your breasts, too. This explains why athletic
girls often have small breasts - their body's fat content is
fairly small. The same is of course true for anorexic girls.
Unfortunately, when you lose weight and your breasts will be
smaller, they often end up sagging more, as the skin is
already stretched but now there is less "stuff" to fill it.
There is no sure way to prevent this.
Some girls end up being flat-chested - Flat-chested girls
lack the fat in breasts but they have the milk producing
system in there and can breastfeed. Please read our page
about being flat-chested to learn more. Being flat-chested
doesn't mean you have to get worried - but if you don't get
your period by age 15, that is a sign of delayed puberty.
hope knowing these facts will ease your mind off from
worrying. You may have heard or read these same facts about
breast development elsewhere, too. They are commonly known
and commonly noted. So the chances are you are developing
just normally and there's no reason to be concerned.
Anorexia and Breasts
Click Here Click
Anorexia, bulimia, or severe dieting will cause the fat to
disappear from breasts, and that is why breasts of an
anorexic girl will look very small, or shrunken.
When such a girl is recovering and gaining weight again, fat
gets deposited back to the breasts. However, it won't always
be the same amount of fat as was there before.
milk ducts and glands shouldn't be affected - if they had
already developed! But if anorexia hits while the breasts
are growing ducts and glands, then that development will
stop since the starved body will stop producing hormones
that drive that growth.
With anorexia, it is hard to say how things will go
afterwards. Most girls become fertile again and resume
menstruation, or continue their pubertal development if it
wasn't finished, but some girls never gain their
menstruation and fertility back even after recovery.
Maturity of the Breast
Once a young woman reaches puberty, and ovulation and the
menstrual cycle begins, the breasts start to mature, forming
real secretory glands at the ends of the milk ducts.
Initially these glands are very primitive and may consist of
only one or two layers of cells surrounded by a base
Between this membrane and the glandular cells are cells of
another type, called myo-epithelial cells, these cells are
the ones that contract and squeeze milk from the gland if
pregnancy occurs and milk production takes place.
With further growth, the lobes of the glands become
separated from one another by dense connective tissue and
fat deposits. This tissue is easily stretched. This is where
the natural enlargement formula comes in and allows the
enlargement that normally occurs during pregnancy when the
glandular elements swell and grow
duct system grows considerably after conception and many
more glands and lobules are formed. This causes the breast
to increase in size as it matures to fulfill its role of
providing food for the baby.
Most women notice that just before menstruation their
breasts enlarge and their nipples become sensitive and even
painful. The texture of the breasts change and they become
rather lumpy, with small discrete swellings that resemble
orange pips in both texture and size. These lumps are glands
in the breast which enlarge in preparation for pregnancy.
pregnancy doesn’t occur, breasts return to their normal size
and the glands become imperceptible to touch within a few
days, ready for re-growth the next month. These changes in
the breast are only one part of many changes that occur in
the female body as the result of the monthly ebb and flow of
the female hormones estrogen and progesterone.
Aging of the Breasts
we get older, our breasts tend to sag and flatten; the
larger the breasts, the more they sag. With the menopause
there is a reduction in stimulation by the hormone oestrogen
to all tissues of the body, including breast tissue; this
results in a reduction in the glandular tissue of the
breasts. So they loose their earlier fullness.
Regular exercise would have however prevented or slowed down
the ageing process. Much of the connective tissue in the
breast is composed of a fibrous protein called collagen,
which needs oestrogen to keep it healthy. Without oestrogen,
it becomes dehydrated and inelastic. Once the collagen has
lost its shape and stretchability it "was" believed that it
could not return to its former state or condition.