When does breastmilk come in? A comprehensive guide

Hydration Moms science
When does breastmilk come in? A comprehensive guide

Breastmilk starts forming well before you give birth. In the middle of the second trimester, your breasts start producing a nutrient-rich substance that comes before the regular breastmilk. But your milk will fully come in, and provide enough to keep your baby healthy and satisfied, 2 to 3 days after birth.

For some moms, this process is slower. (For new moms, it can take up to 5 days postpartum. For some moms, it takes even longer.) If your breastmilk doesn’t come in by day 4, or doesn’t come in fully, there are techniques you can use to encourage milk production.


The first milk your baby will drink

The first milk your breasts produce is called colostrum. It’s a thick liquid, dense with nutrients, calories, protein, and antibodies that fight disease. It’s exactly what a tiny and vulnerable baby needs. It’s yellow rather than white, and it’s so valuable that it’s often called liquid gold.

A newborn’s stomach is only the size of a marble when he is born, and he can only drink about a tablespoon. For the first few days, your body produces colostrum rather than regular milk because the baby’s stomach couldn’t hold enough milk to get enough nutrients. Colostrum has the perfect concentration to nourish your baby in a small volume.

That’s why it’s ok that your breasts take 2-5 days to get milk production into full swing. Your baby won’t starve—in fact, he’s getting some of the most nutritious food he will ever eat.

The small amount of colostrum gradually becomes a larger amount of transitional milk over those 2-5 days. For most moms, full milk production is underway by the 5th day. (Fully mature milk comes in around 10-15 days after childbirth.)

Most healthy babies need 2-10 mL per feeding for the first day, and that increases to 1-2 oz by day 3.



Three things that trigger breastmilk production


 The main event that tells your body to start produce full milk is the birth itself—specifically, the delivery of the placenta. This creates biochemical messages, using the hormone prolactin, to stimulate your breasts to produce milk within 30 to 40 hours. Prolactin is highest during the 2 hours after birth.

Breastfeed your baby within an hour after birth, if possible. If your baby is in the NICU, hand-express the colostrum so the nurses can give it to the baby and so that your production is established quickly. This tells your body that the colostrum is now needed, and it should make more.

For most moms, milk comes in by day 3. For about a quarter of moms, though, it takes longer.

It can take up to 5 days without endangering your baby, since you are still producing colostrum. If you reach the 6th day and still aren’t producing very much, talk to your IBCLC-certified lactation consultant. You can also consider trying a nutritional supplement tailored for breastfeeding support.


The second trigger is the actual action of breastfeeding. When your baby suckles on your breast, it sends biochemical messages that tell your breasts more milk is needed, so more needs to be produced. Prolactin is at work again; after your baby finishes a feed, prolactin tells your alveoli (sacs filled with cells that produce milk) to produce more milk for the next feeding.

Prolactin reaches high levels at night, so breastfeeding during the night is not only crucial for your newborn’s health but also vital for establishing milk production.

Although your milk may still come in if you don’t breastfeed, it will usually come in faster if you breastfeed (or pump) regularly. Feed your baby at least 8 to 12 times a day, for your baby’s own nutritional needs and to help train your body to produce enough milk to keep up.

Skin-to-skin contact

When you snuggle with your baby, skin to skin, this releases hormones that remind your body it has a baby to love and nourish. It increases bonding and milk production. Isn’t this beautiful?


How to tell when your milk has come in

You’ll notice physical changes to your breast, behavioral changes in your baby, and visual changes in the milk.

Changes in the breasts

You may experience:

  • Swelling
  • A sense of fullness
  • Heaviness
  • Warmth, both internal and when touched
  • Engorgement (feeling hard)
  • Tingling
  • Leaking milk

Changes in the baby’s eating behaviors

Your baby’s feeding patterns might change. She could suck more deeply and more slowly, now that she is getting a stronger flow of milk.

Changes in the milk

If you’re leaking, or if you gently express milk or use a breast pump, you can evaluate its appearance. Colostrum is thick and yellow, whereas transitional milk is thin and white. If it’s thin and white, then you’re well on your way!

Trust your instincts

Although appraising your milk supply can be difficult or confusing, studies have shown that mothers have good instincts about determining whether their milk has come in.

 Woman happily breastfeeding her baby

Factors that could delay your milk from coming in

If your breastmilk hasn’t come in by day 4, it’s called delayed onset of lactation (DOL). It is not your fault, and it doesn’t mean your body can’t nourish your baby. Breastmilk production is a complex process that can be influenced by a multitude of factors, and many of them are outside your control. (Still, there are many things you can do to encourage your body to produce more milk.)

For most of these factors, there are ways you can address the problem or improve the issue. Other times, you just need to keep going.

A difficult or complicated childbirth

Any number of factors during labor and delivery, from a long IV to a long pushing stage, can lead to low milk supply.

Most of these things are uncontrollable, like having an intense or traumatic birth, blood loss, a retained placenta, or an infection. Some factors are sometimes optional but often necessary, like having a c-section. Others are up to you, like using pain medications.

It’s your first baby

First-time mamas usually take one day longer for their breastmilk to come in. Moms who previously had babies tend to reach full production faster because their bodies remember what to do.


Mothers who are obese are more likely to experience DOL.

Medical conditions

Mothers with diabetes or thyroid conditions may have a harder time establishing breastfeeding.

Don’t give up

None of these factors mean you can’t breastfeed. You may just need extra support.


Factors that could slow your milk production

With these factors, your milk will come in on schedule, but with less volume.

Preterm birth

Preterm birth slows breastmilk production because your body hasn’t had enough time to prepare.

Underdeveloped breasts

This is called mammary hypoplasia or insufficient glandular tissue. It’s unrelated to the size of your breasts—it’s more about the tissue composition. Moms with small breasts can make just as much milk as moms with large breasts, although they may need to feed more often.

Flat or inverted nipples

Nonstandard areola anatomy can sometimes make breastfeeding more difficult, but that difficulty isn’t a sure thing, and it can usually be fixed by using a nipple shield.

Breast surgery or injury

This could affect the tissues that make milk, or it could affect the nerve endings that signal the letdown reflex.

Pierced nipples

Piercings can interfere with breastfeeding. You may need to remove your piercing.


Many medications—including the birth control pill—can slow milk production.

Anything that interferes with breastfeeding during days 1-3

If you are sick after birth, for example, and can’t feed or pump on a schedule, then your milk will probably come in more slowly.


What to do if your breastmilk hasn’t come in by day 4

This can be deeply frustrating, but it doesn’t need to be the end of your breastfeeding journey. Here’s how to tackle the situation.

If you're wondering, "Will my body ever make enough milk for my baby?" The answer is yes! By two weeks postpartum, most women are able to establish a steady supply of mature breastmilk.

Stimulate breastmilk production as much as possible

Skin-on-skin snuggles. Frequent feedings. A proper latch. A healthy diet. Do everything you can to set your breasts up for success. A nutritional supplement designed for breastfeeding moms can also help.

Fix any problems

If you have a nipple piercing, take it out. If you’re on a medication that interferes with breastfeeding, talk to your doctor about a solution. If you had a difficult labor, get plenty of rest.

Most problems with your milk coming in are out of your control—but if you can control something, address it head-on.

Keep a close eye on your baby

If your baby loses more than 7% of his body weight, he might not be getting enough milk to stay healthy and keep growing. At this point, you need to get professional breastfeeding help.

If you notice signs of dehydration or jaundice, get help from your pediatrician immediately.

Other signs that signal an insufficient supply of breastmilk: hunger after eating, extra long feedings, unusual crying, signs of frustration, less than six wet diapers a day, and fewer dirty diapers. Ask for breastfeeding help if you notice these signs.

Work with a lactation consultant

The next step is finding a board-certified lactation consultant through the IBCLC who can evaluate your breastfeeding and offer crucial advice. 

Your lactation consultant can find and correct any errors in how you breastfeed, give diet recommendations, and suggest any additional triggers, supplements, habits, and support that can help you increase your milk production. She will also guide you in monitoring your baby’s weight and health.


What to do if you’re struggling emotionally

Breastfeeding can be a challenging journey, especially if it doesn’t go as planned. But if you still want to breastfeed your child, don’t give up. With personal support and informational support, the vast majority of women who want to breastfeed are able to establish a healthy milk supply. Hang in there.