If you’ve ever been pregnant or if you are pregnant
now, you’ve probably noticed a metamorphosis in your bra cups. The physical changes (tender, swollen breasts) may be one of the earliest clues that you have conceived. Many experts believe that the color change in the areola may also be helpful when it comes to breastfeeding.
What’s going on
Perhaps what’s even more remarkable than visible
changes in the extensive changes that are taking
place inside of your breasts. The developing
placenta stimulates the release of estrogen and
progesterone, which will, in turn, stimulate the
the complex biological system that helps to make lactation
Before you get pregnant, a combination of supportive
tissue, milk glands, and fat make up the larger
portions of your breast. The fact is, your newly
swollen breasts have been preparing for your
pregnancy since you were in your mother’s womb!
When you were born, your main milk ducts had already formed. Your mammary glands stayed quiet until
you reached puberty when a flood of the female
hormone estrogen caused them to grow and also to
swell. During pregnancy, those glands will kick
into high gear.
Before your baby arrives, glandular tissue has
replaced a majority of the fat cells and accounts
for your bigger than before breasts. Each breast
may get as much as 1 1/2 pounds heavier
Nestled among the fatty cells and glandular tissue
is an intricate network of channels or canals known
as the milk ducts. The pregnancy hormones will
cause these ducts to increase in both number and
size, with the ducts branching off into smaller
canals near the chest wall known as ductules.
At the end of each duct is a cluster of smaller sacs known as alveoli. The cluster of alveoli is known as a lobule, while a cluster of the lobule is known as a lobe. Each breast will contain around
15 – 20 lobes, with one milk duct for every lobe.
The milk is produced inside of the alveoli, which
is surrounded by tiny muscles that squeeze the
glands and help to push the milk out into the
ductules. Those ductules will lead to a bigger
duct that widens into a milk pool directly below
The milk pools will act as reservoirs that hold the milk until your baby sucks it through the tiny openings in your nipples.
Mother Nature is so smart that your milk duct
the system will become fully developed around the time
of your second trimester, so you can properly
breastfeed your baby even if he or she arrives
earlier than you are anticipating.