What is Lactation?

The process during which your breasts' mammary glands produce and release milk is known as lactation. When hormonal shifts during pregnancy tell the mammary glands to start producing milk in anticipation of the baby's birth, lactation starts. The same hormones your body produces during pregnancy can also be used to stimulate lactation outside of pregnancy. When your body quits producing milk, lactation is over.

Tucking your baby directly from your breasts is known as breastfeeding or nursing. You may also feed your baby milk, which you have expressed or pumped out of your breast and stored in a bottle.

Where does the breast milk come from?

Breast milk originates from the mammary glands within your breasts. The glands contain multiple parts that cooperate to create and secrete milk:

Alveoli: These small, grape-shaped sacs form and store milk. A group of alveoli is called lobules; one lobule links to a lobe.
Milk ducts: One milk duct links to each lobe. You may have a maximum of 20 lobes and one milk duct per lobe. Milk ducts transport milk from alveoli lobules to your nipples.
Areola: The pigmented zone around your nipple with nerve endings that inform your body when it is time to let milk out. To let milk out, the whole areola must be stimulated.
Nipple: Your nipple has several tiny pores (up to around 20) that release milk. Nipples on your breast have nerves that react to suckling (by a baby, your hands, or a breast pump). This causes your brain to release milk from the alveoli down the milk ducts and out your nipple.

It is useful to imagine the lactation system as a big tree. Your nipple is the trunk, the branches are the milk ducts, and the leaves are the alveoli.

Why do humans lactate?

The first and main reason you lactate is to nourish a baby. Lactation is a biological, hormonal reaction during pregnancy and afterwards to nourish a new baby. Your body initiates certain hormones to produce milk and ejection (milk release). All mammals lactate for this reason and you can induce lactation in anyone with the appropriate hormone medications.

What initiates lactation?

A chain of hormonal events, which starts when you're pregnant, sets off the lactation process, which is referred to as lactogenesis.

Stage one lactogenesis starts about the 16th week of pregnancy and continues until a few days after birth.

Estrogen and progesterone increase and your milk ducts increase in number and size. This makes your breasts feel fuller, and your mammary glands start preparing for milk production.
Your nipples become darker and your areolas become bigger.
Your Montgomery glands (little bumps on the areola) secrete an oil to grease your nipple.
Your body starts producing colostrum. It's very nutritious and satiating and is your baby's first milk.

Stage two lactogenesis: This stage begins around two or three days after giving birth. It's when milk-making increases.

After the delivery of your baby and placenta, prolactin takes over due to a sharp decline in your levels of progesterone and estrogen.
The hormone that causes milk production is called prolactin.
At this point, you'll notice a significant rise in milk output. It's frequently called "milk coming in."
Your breasts are frequently unpleasant, painful, or tender due to engorgement, or being overly full with milk.

Stage three lactogenesis: This is the rest of the time you produce milk.

Lactation will usually keep going as long as milk is taken from your breast.

The more milk that is taken out, the more milk your body produces to fill that space. Feeding or pumping lots will make your body produce more milk.

Hormones for lactation

The hormone prolactin regulates how much milk you make, and your body starts producing prolactin at the beginning of pregnancy. Initially, the pregnant woman has such high levels of estrogen, progesterone and other pregnancy hormones that they squelch the prolactin. After you give birth to the placenta, those pregnancy hormones decrease and prolactin dominates.

Your baby nurses stimulate nerves that tell your body to release oxytocin and prolactin. Prolactin causes the alveoli to produce milk and oxytocin causes contractions of the muscles that force them out of the alveoli and through the milk ducts.

When milk is released, it's referred to as a "letdown," and it will take approximately 30 seconds of suckling before the letdown is released. Since you can't control which breast the hormones go to, the letdown will cause milk to drip from both nipples.

If you're not pregnant, inducing lactation involves taking medication that replicates hormones that your body produces during pregnancy. Sucking on the nipple can stimulate lactation, either with a breast pump or by a baby. This is a highly complex process that requires working closely with a healthcare provider who knows you and has experience in inducing lactation.

When do you lactate when you're pregnant?

Lactation starts as early as a few weeks into your second trimester of pregnancy. As levels of estrogen and progesterone increase, your body is getting ready for lactation by expanding the number of milk ducts that are present in your breasts, and those milk ducts will carry milk from the alveoli to your nipples. Roughly in the middle of pregnancy, your body produces colostrum, which is your baby's first milk.

Can you lactate when not pregnant?

Yes, you can lactate if you're not pregnant. Inducing lactation is a complicated process that typically uses hormone-mimicking drugs for a few months to induce milk production. The second half of lactation is expressing the milk through your nipple. Infant suckling stimulation, pumping with a breast pump, or hand-expressing triggers the brain to release the milk. You can have a healthcare provider assist you with this.

How to stop lactation?

There are several reasons that you may need to stop lactation. You can stop lactating either naturally or by the use of hormonal drugs.

Natural milk suppression

Lactation is a process of demand and supply. Your milk supply decreases gradually as your baby depends less on breast milk or if you cut back on the number of times you pump or nurse. If you lower the amount of milk taken out of your breasts, your body will reduce milk production.

Suppressing your milk might be uncomfortable, and most individuals will get engorged (the medical term for overfull breasts). You can also leak milk or get a clogged milk duct. But you can relieve that pain by taking an over-the-counter painkiller, using a firm bra, or applying an ice pack to your breasts.

Medication suppression

Medications may also be an alternative if you need to quit making milk. Your doctor can tell you more about lactation-suppressing medications, including the advantages and potential side effects.

Where are the mammary glands found?

Mammary glands are also referred to as breasts and are present in everyone. They are on your chest and comprise connective tissue, fat and glandular tissue specific to producing milk. The female glandular tissue is different in that it has the alveoli and lobules required to produce milk. Females also possess significantly more glandular tissue.

What are typical disorders or conditions that impact your ability to lactate?

There are differences in lactation capacity and milk production duration. While some struggle to create enough milk for their infant, others can continue to supply milk for years.

Hormonal levels and circumstances are among the primary factors that can affect breastfeeding or lactation.

Drugs.
Undergoing radiation treatment previously.
Injury to your nipples or breast.
Breast surgery, such as breast reconstruction or augmentation.
Additional illnesses, such as HIV infection.
Alcohol and drug use.

If you're nursing or expressing your milk to bottle-feed your baby, always get advice from your healthcare provider before using new medicines or treatments. A lot of medicines are passed to your baby in your breast milk, which can be harmful to your baby.

What is lactational amenorrhea?

Lactation amenorrhea (ah-men-oh-re-uh) is when you are not menstruating (getting a period) because of lactation. When you're lactating, your body makes prolactin, the hormone that synthesizes milk. Prolactin decreases the level of luteinizing hormone (LH) in your body, which stimulates the release of an egg during ovulation. If you're not making enough LH, you're unable to ovulate or have your period. How long you can be amenorrheic from lactation depends on a few months or until you're fully finished lactating.

Does lactation lower my risk for any diseases?

Research has indicated that breastfeeding lowers your risk of breast and ovarian cancers. It may also decrease your risk for Type 2 diabetes and high blood pressure.

How do I maintain milk production?

Sustaining lactation is primarily supply and demand. The more your baby nurses or the more you pump with a breast pump, the more your body will produce. There are methods of suppressing lactation with oral contraceptives or hormones. If you want to sustain lactation, some of the things you want to do are:

Keep nursing on-demand or pumping milk regularly (every four hours or so).
Eat a good diet with sufficient calories. Low-calorie diets may slow milk supply down.
Drink lots of water to be well-hydrated. Breast milk is mostly water.
Do not smoke, use drugs or drink alcohol. All these may lower your supply and pass on to your milk.