When Does Breast Milk Come In? Plus, What to Do If It Doesn’t

Getting ready to breastfeed your new baby is a very exciting time—there are so many amazing benefits for both mama and baby—but it’s also one filled with questions and concerns (especially if you’ve never breastfed before). Before you get into the nitty-gritty of it all—positions, pumps, feeding in public, etc—you’ll probably have one major question on your mind: “When does breast milk come in?”

We’ll break it all down, including:

• When breast milk comes in
• How breast milk comes in
• Signs your milk is coming in
• Plus, what to do if your milk isn’t flowing

When Does Breast Milk Come In?

The short answer: Most moms experience a surge in breast milk about 2 to 5 days after giving birth.

But… it’s a little more complicated than that. To get technical, you’ve actually been producing breast milk for your baby since the middle of your pregnancy—even if your breasts don’t feel very full or heavy and you didn’t leak any milk. Let’s unpack this fascinating process:

It All Starts With Colostrum…

According to La Leche League, your breasts start to produce colostrum—a yellow-gold colored milk full of wholesome, dense nutrition, antibodies, and other disease-fighting agents—during pregnancy. This type of breast milk starts to come in about 12-18 weeks into pregnancy. Some women even begin leaking colostrum during pregnancy. If you noticed yellow-crusty remnants on your nipples during pregnancy or some wetness on your bra, shirt, or sheets, chances are that was a bit of leaking colostrum.

Women begin producing colostrum during pregnancy, because this is food that it needs to be available to your baby as soon as they are born. Though colostrum is often referred to as baby’s “first milk,” you’ll only produce a few teaspoons at a time. This is sufficient for baby in those first few days, because their stomach capacity is very small in the first few days following birth.

Then Colostrum Gives Way to Mature Milk…

Over the course of the first few days after birth, your colostrum begins to change as more mature breast milk starts to come in. Colostrum gradually increases in amount, and changes from a thicker, yellow fluid to a thinner, whiter mature milk.

The process of your milk “coming in,” or turning into mature milk, is controlled by your hormones. Once you deliver the placenta and your progesterone and estrogen levels decline, your body increases production of a hormone called prolactin, which gets the milk production process started.

• Most women notice this change from colostrum to mature milk around two to three days following birth.
• But some women don’t notice this change until day four, five, or even later.

Although you technically don’t have to do anything to ensure that your milk comes in quickly and plentifully, breastfeeding frequently and practicing skin-to-skin can help stimulate prolactin production to ensure a smooth transition to mature milk.

What Does It Feel Like When Your Milk Comes In?

Every mom has a slightly different experience when their breast milk comes in. It’s totally normal if you don’t end up feeling very engorged—extra fullness doesn’t necessarily mean you are making more milk.

In general, here are some of the ways that moms describe the way it feels when your milk comes in:

• Your breasts will start to feel full and heavy
• You may feel some tingling sensations, especially during let-down
• The veins in your breasts may stand out more
• Your breasts may feel warm to the touch
• You may begin to leak more
• You may notice your baby gulping and swallowing more

How Much Bigger Will My Breasts Get When My Milk Comes In?

Every woman is different in terms of how much bigger her breasts get once her milk comes in.

• Some women—especially if they have larger breasts to begin with—don’t notice much of a change in breast size.
• Other mothers notice a significant difference once their milk comes in.

Generally, a woman’s breast size increases about two to four breast sizes once her milk comes in. But as your breast milk supply levels out, that initial dramatic increase generally becomes less pronounced. You may notice your breasts slightly decrease in size about two to three days after your milk comes in and again in about four to five weeks, when your supply stabilizes at bit more.

Still, your breasts will probably be slightly larger than usual for the first few months of breastfeeding, and will likely not decrease significantly until your baby is breastfeeding less—likely after your baby starts eating solids, sometime around six to eight months.

Why Hasn’t My Milk Come in Yet?

Although the timeline varies slightly, most women notice their breast milk starts to come in within a week of giving birth. If your milk hasn’t come in by day five or so, you’ll want to reach out to your child’s pediatrician and consult with a lactation consultant. 

And always be on the lookout for signs of dehydration and hunger in child, including:

• unusual lethargy,
• a lack of wet diapers (baby should have at least 5-6 wet diapers per day after the first few days),
• or a sunken soft spot.

Contact your pediatrician or local emergency room immediately for help.

At the end of the day, a fed baby is what’s most important and you may need to supplement with formula. Again, your child’s doctor and a lactation consultant will be able to counsel you on this issue.

Keep in mind that if you have a delay in your milk coming in, there is almost always something that can be done to increase your milk supply. (More on that below.)

Risk Factors For Delayed Milk Production

There are several reasons why your breast milk might not be coming in. Once you are able to identify the reason, you can figure out how to remedy it. Your lactation consultant can help you come up with a plan to increase your milk production (and possibly supplement your baby) while you wait for your supply to increase. Remember: A fed baby is always most important!

Here are some reasons why your milk production may be delayed:

1. First-time Moms: Studies show that first-time moms often experience a slight delay in milk production. On average, their milk comes in a day or two later than moms of more than one.
2. C-section: According to research, having a c-section can delay the onset of milk production. You can optimize breastfeeding success by practicing early skin-to-skin and breastfeeding frequently.
3. Prolonged or traumatic labor: Studies suggest stress or trauma associated with labor and very lengthy labors may slow down the onset of milk coming in.
4. Pain medication: Research suggests that mothers who received pain medications during labor were more likely to report delayed lactation, regardless of delivery method.
5. Maternal health factors: Although you can’t always pinpoint exactly what may be causing a delay in milk production, there are certain maternal health factors that can contribute to this, including maternal obesity, diabetes, thyroid imbalances, polycystic ovarian syndrome, and postpartum hemorrhaging.
6. Breast issues: A history of breast surgeries (like implants or reductions) can slow the process of when your breast milk starts to come in. Or, if you have flat or inverted nipples, your baby may have trouble latching or suckling, which can also slow down milk production in the early days.
7. Medication: Most medications are safe for breastfeeding and will not impact your milk supply. However, some medications (birth control and cold medicine, for example) tend to decrease milk supply. For information about a particular medication you are taking, check LactMed. It’s a government-run website that describes the safety and side effects of different medications on your baby and your milk supply.
8. Latch issues: If your baby is having trouble latching, you may notice low milk supply. Getting a stronger, deeper latch should help speed things along, but in some cases this may signal an anatomical issue, like tongue tie or lip tie.

What to Do if Your Milk Isn’t Coming In

If your breast milk isn’t coming in, just breathe. There are so many things you can do to remedy the situation, and even if you end up dealing with a low milk supply issue, you have options.

The first thing you should do is reach out to a lactation consultant as soon as you have any concerns about your milk coming in. Here are some strategies your lactation consultant might suggest to get that milk flowing:

1. Feed, Feed, Feed: Milk production is a “supply and demand” system, so the more milk you take out, the more milk you will make.
2. Skin-to-skin: Holding your baby skin to skin increases prolactin levels, which jumpstart the milk production process.
3. Pumping: If you can’t directly breastfeed, or if direct breastfeeding has not been effective, pumping can help jump-start your milk supply. Power pumping may be particularly helpful.
4. Don’t wait until baby is hungry: Feeding on demand means not waiting until your baby is wailing with hunger to feed them. Feed your baby as soon as they begin to show signs of hunger (licking lips, rooting, sucking on fists). This will ensure you are feeding frequently.
5. Eat nutrient dense meals and HYDRATE: You don’t have to eat a perfect diet to produce enough milk for your baby, but neglecting your need for healthy, wholesome food will deplete you, stress out your bodily systems, and can make it difficult to produce a strong milk supply. You need to increase your regular caloric intake by 500 calories a day to support early and exclusive breastfeeding.
6. Try not to stress: Easier said than done? Yes, but stress negatively impacts production. Try to think positively. And get enough sleep (sleep when baby sleeps). With a little help, most women can get their milk flowing in no time. Find out how to reduce stress.

The Bottom Line

Those early days as you wait for your milk to come in can be stressful. There is so much uncertainty, and you might be confused about what is happening with your body and your baby. Have faith in your body’s ability to make the milk your baby needs. And always reach out for help when needed.

Remember: If you do end up having an issue with your milk coming in, there are so many ways to remedy the situation. And even if there is a delay or you end up with low milk supply, you have not failed. Breastfeeding isn’t all or nothing. The most important thing is a happy, well-nourished baby and mama.