We are searching data for your request:
Upon completion, a link will appear to access the found materials.
The process starts during pregnancy
If you're pregnant, you may have noticed changes in your breasts, such as tenderness, swelling, and darkened nipples and areolas (the circle of skin surrounding your nipple). These changes may be some of the earliest clues that you've conceived.
No worries if you don't notice any changes in your breasts during pregnancy, though. That's also perfectly normal, as your body is still preparing to make milk.
What's going on inside your breasts
Perhaps even more remarkable than any visible transformation are the extensive changes taking place inside your breasts. The developing placenta stimulates the release of the hormones estrogen and progesterone, which in turn stimulate the complex biological system that makes milk production possible.
Before pregnancy, supportive tissue, milk glands, and protective fat make up a large portion of your breasts. The amount of fatty tissue is an inherited trait and varies among women, which is why breasts come in such a variety of sizes and shapes. The size of your breasts doesn't determine your ability to produce milk or breastfeed.
Your breasts have been preparing for your pregnancy since you were in your mother's womb. (By the time you were born, your main milk ducts – a network of canals designed to transport milk through your breasts – had already formed.)
Your milk glands stayed quiet until puberty, when a flood of estrogen caused them to grow and swell. During pregnancy, those glands shift into high gear.
Nestled amid the fat cells and glandular tissue are the milk ducts, an intricate network of channels. Pregnancy hormones cause the milk ducts to grow in number and size.
The ducts branch off into smaller channels near the chest wall called ductules. At the end of each ductule is a cluster of small, grapelike sacs called alveoli. A cluster of alveoli is called a lobule; a cluster of lobules is called a lobe. Each breast contains up to 20 lobes, with one milk duct for every lobe.
Prompted by the hormone prolactin, the alveoli take proteins, sugars, and fat from your blood supply and make breast milk. A network of cells surrounding the alveoli squeeze the glands and push the milk out into the ductules, which lead to the ducts. (You can think of the milk ducts as individual straws, some of which merge so that about eight or nine end at the tip of your nipple to deliver milk to your baby.)
Your milk duct system becomes fully developed sometime during your second trimester, so you can make milk for your baby even if he arrives prematurely.
By the time your baby is born, your glandular tissue will likely have expanded significantly. Each breast may get as much as 1 1/2 pounds heavier!
What is colostrum?
Colostrum, sometimes called "liquid gold," is the first milk your body produces. It can be clear, white, yellow, or orange, and it's often thick and sticky. During the first days of breastfeeding, your newborn will be perfectly nourished by this nutrient-rich, high-protein, low-fat, easily digestible liquid.
Your body starts making colostrum about three to four months into pregnancy, and a few drops may leak from your breasts now and then during the final weeks of pregnancy. (This happens to some women as early as the second trimester.)
This "first milk" is produced as the cells in the center of the alveoli dissolve and flow through the milk ducts to the nipple. Colostrum is higher in protein, minerals, salt, vitamin A, nitrogen, white blood cells, and certain antibodies, and it has less fat and sugar than mature milk.
It's also full of unique disease-fighting antibodies called immunoglobulins that strengthen your baby's immune system. When you feed your newborn colostrum, it's as though you're giving him his first vaccination.
Colostrum also has a slightly laxative effect that helps a newborn clear his gastrointestinal tract of meconium – the stool that accumulated in his bowel while he was in the womb. Getting rid of this black tarry stool soon after birth reduces the risk of jaundice.
Your baby's tummy is tiny, so he'll take just a tiny amount of milk at first – about a teaspoon of colostrum each time he nurses. But a little colostrum goes a long way. You may not feel as if you're producing much (and your breasts won't feel full yet), but each drop is packed with nutritional and protective components.
During the next few days, your milk will transition from colostrum to mature milk (though some colostrum will continue to show up in your milk for a few weeks).
Production heats up after your baby is born
You'll move into the next phase of milk production within two to four days of delivering your baby. (Second-time moms may find that their milk surge comes earlier than it did the first time around.)
Once you deliver your placenta, the estrogen and progesterone levels in your body suddenly drop. At the same time, the level of prolactin rises – this signals your body to make milk.
As your body moves through the stages of lactation, it pumps extra blood into the alveoli, making your breasts firm and full. Swollen blood vessels and extra swelling in the breast tissue itself, combined with an abundance of milk and IV fluid given during labor, may make your breasts temporarily painful and engorged, but your baby will be nursing frequently in the first weeks, which will help relieve the discomfort.
How milk flows from you to your baby
For your milk to flow from your breasts, it must be "let down" or released from the internal alveoli.
Here's how it happens: Your baby's sucking stimulates the pituitary gland to release oxytocin and prolactin into your bloodstream. (The same thing can happen when you merely think of your baby nursing or hear his cries.) When the milk reaches your breast, oxytocin causes the cells around the milk-filled alveoli to contract and squeeze. The nourishing liquid then flows into the ducts.
When your baby suckles, he compresses the nipple and areola, creating negative pressure. That – along with the internal rush of milk from the "letdown" reflex – delivers the milk into his mouth.
As your milk flow increases, the contraction of the milk-filled alveoli may create a tingling, stinging, burning, or prickling sensation in your breasts. Your milk may drip or even spray during letdown. (If this happens at an inconvenient time, try crossing your arms in front of your breasts, applying gentle pressure to stop the flow. Nursing pads can also be placed inside your bra to help absorb the milk.)
You may feel calm, satisfied, and joyful as you nurse. No wonder some people call oxytocin the hormone of love! You also may feel sleepy and thirsty. These are signs that your baby is stimulating the breast.
By the way, you may also feel some cramps in your uterus as your newborn feeds in the days after birth. This means that oxytocin is helping to shrink your uterus back to its pre-pregnancy size. (This same hormone caused your uterus to contract during labor.) The discomfort is usually mild, but it can be painful, especially if this isn't your first baby. Your provider may recommend ibuprofen or prescribe a pain medication.
What's in breast milk?
Mature breast milk is perfectly designed and contains water, fat, carbohydrates, protein, vitamins and minerals, and amino acids. It also contains white blood cells, antibodies, enzymes, and other substances that boost your baby's immune defenses.
There are more than 200 known beneficial components in breast milk, with more being discovered all the time. For example, researchers now believe that a fatty acid in breast milk promotes the growth of a baby's brain and retina, and may even enhance cognitive development. Many of these elements, including infection-fighting white blood cells, can't be manufactured.
Mature milk comes in approximately two to four days after your baby's birth, depending on the frequency of nursing in the first hours and days after birth. Your milk production will adjust to accommodate your baby's appetite and how often she nurses.
During the course of a feeding, breast milk changes from foremilk, high in water and lactose, to hindmilk, high in fat and calories. The quantity of milk you produce increases along with your baby's weight and appetite until solid food becomes a daily part of her diet.
How breast milk changes for your baby
Breast milk is the ultimate personalized food. One of the wonderful characteristics of human milk is the way it changes to meet your baby's needs as he grows.
The breast milk a mother produces for her premature baby differs from the milk she would produce for a full-term newborn, and that differs from the milk she'll have for her 6-month-old baby. All breast milk, however, contains exactly the nutritional and protective components needed most by each baby at every age.