When Does Breast Milk Come In? Signs and Timeline

While you can start breastfeeding your baby as soon as she’s born, it’ll take a few days for your milk supply to establish itself fully, and your milk will change during your baby’s first few weeks.

Here’s a breakdown of what to expect as your breast milk “comes in” and some tips for navigating this process.

Your body produces breast milk in three distinct stages. At each stage, the milk you produce is different, which means it has a slightly different nourishment profile that’s tailored to your baby’s developmental needs. 1

Stage 1: Colostrum

Your body can begin producing colostrum—the first milk your baby will feed on—well before she’s born, as early as 16 weeks into your pregnancy.

Many people call colostrum “liquid gold” due to its yellow color and rich concentration of antibodies, protein, vitamins, and minerals. It boosts your newborn’s immune system and protects her from infections with antibodies like Immunoglobulin A (IgA). It also reduces the chance of her developing allergies. 2

Another major role colostrum plays is as a laxative to help your baby pass her first stool (meconium). This prevents her from reabsorbing the waste products (bilirubin) in the meconium, which can cause infant jaundice.

Since your newborn’s stomach is very small, you won’t produce very much colostrum, and she’ll only eat a small amount at first. By frequently nursing or pumping, you’ll encourage your body to transition to the next stage.

Stage 2: Transitional milk

Transitional milk is the milk that “comes in” that most women anticipate. It arrives two to five days postpartum. It’s typically lighter in color, sometimes a bluish-white, and your body produces it in larger quantities than colostrum.

Transitional milk is higher in fat and calories, which supports your baby’s rapid growth in her early days. You may experience breast engorgement and leaking from the nipples as your milk supply increases. 3

Stage 3: Mature milk

Around 10–15 days postpartum, you’ll finally produce the mature milk that will provide your baby’s long-term nutrition.

Mature milk is 87% water, making it thinner than transitional milk, but that last 13% contains all the essential fats, carbohydrates, and proteins that your growing infant needs. 4

The composition of your mature milk will also change as your baby grows, although not as dramatically as it did when it transitioned between the previous stages.

The timeline described above is just a guideline. Your body will let you know when your milk is coming in.

There are several telltale signs that indicate your milk is transitioning from colostrum to transitional milk. As mentioned, breast engorgement is a big one; your breasts may feel larger, firmer, warmer, and heavier than usual. Unfortunately, many women even find engorgement painful.

You may also experience:

• Tingling sensation: You might experience a tingling or “pins and needles” sensation as your baby nurses. This is the let-down reflex (also called the oxytocin reflex), which helps your breast release milk. 5
• Changes in your baby’s feeding: You’ll likely notice your baby swallowing more rhythmically and drinking larger amounts at each feeding. Hearing your baby swallow while feeding is a good sign. She may even get “milk drunk,” meaning she’ll appear sleepy and satisfied after feeding.

When you see your milk shift from thick, yellowish colostrum to a creamier, white or whitish-blue liquid, it’s a sign that your transition is complete and your milk has fully come in.

While your milk should arrive within 2–5 days of giving birth, some women experience a delay in their milk coming in.

Several factors can contribute to this. 6 Chief among them is simply not nursing (or pumping) enough; if you lean on formula a lot, even in the beginning, the infrequent feeding schedule can signal to your body that there’s no demand for a larger milk supply.

Medical conditions and anatomical issues

Certain medical conditions, including obesity, diabetes, polycystic ovary syndrome (PCOS),  and thyroid issues can impact your milk supply. So can previous breast surgeries and breast hypoplasia (a condition characterized by the underdevelopment of breast tissue). 7

Some medications, such as certain decongestants or antihistamines, can also decrease your milk supply. 8

Issues during labor and delivery

If you had a rough labor, that can also delay your milk production. High levels of stress during and after delivery can interfere with the oxytocin reflex that stimulates milk production. 9

You may have issues producing enough milk if you had: 10

• A Cesarean delivery (C-section)
• Premature labor
• Significant blood loss during delivery
• Retention of placental tissue after giving birth 11

What to do if your milk is delayed

Regardless of the reason, if you’re worried that your milk isn’t coming in, don’t panic. The first step is to speak with your OB/GYN or a certified lactation consultant. They’ll help you figure out the root cause and come up with a treatment plan.

Here are some steps they may recommend:

• Frequent breast stimulation: Consistent milk removal (pumping or feeding) signals your body to produce more milk. 6 Acquiring (either buying or renting) a hospital-grade pump can help with this. After you nurse or pump, you may need to express your colostrum by hand to stimulate your milk production.
• Checking your latch: It’s important to make sure your baby is properly latched so that she can fully drain your breast, which will signal your body to produce more milk.
• Galactagogues: This rather elaborate-looking term refers to certain foods, herbs, and medications that may increase your milk supply. You should discuss this in detail, including any potential side effects, with your doctor before trying this; don’t make any big changes to your diet or start taking a new type of medicine without getting their approval. 12

It’s also possible that your doctor will just prescribe old-fashioned rest. Fatigue and stress can impact your milk supply, so this should be a priority. It probably goes without saying that you should also make sure you support your overall health by drinking plenty of water and eating well.

Be prepared for your pediatrician to recommend temporarily supplementing your baby’s diet with formula or donor milk to ensure she gets enough nourishment while you work on increasing your milk supply.

It’s normal to find breastfeeding a bit challenging, especially if you’re a first-time mother. Your body has to do a lot of work to produce milk for your baby, and it can take a toll.

Here are some of the most common difficulties you might face and ways to deal with them: 13

• Sore nipples: Some tenderness is normal and often inevitable, but soreness can be exacerbated by an imperfect latch. Pay attention to your baby’s latch and try different nursing positions or applying lanolin cream.
• Clogged ducts: You can relieve the discomfort of clogged ducts by massaging the affected area and applying warm compresses. Nursing frequently on the affected side can loosen the clog.
• Breast engorgement: The best thing to do for this is to nurse your baby on-demand, ensuring that you fully drain your breasts each time. If your baby doesn’t drain your breast herself, you can express it by hand or by pumping before feeding her. With that said, don’t go overboard with pumping, as this can make postpartum swelling of the breasts even worse. 13

If your baby was born prematurely or has problems latching, you can use nipple shields to improve her suction. You may want to think twice about using them long-term, as this could increase your risk of mastitis and other breastfeeding issues. 14

Signs of mastitis

Be on the lookout for signs of breast infections, especially since they can easily be passed between you and your baby. Inflammation of the breast (known as mastitis) is one to watch out for, although it can also be a sign of another nursing issue (like a clogged milk duct).

Look out for the following symptoms:

• Redness, warmth, and pain in the breast
• Flu-like symptoms (including fever, body aches, nausea, and fatigue)

If you have a fever that exceeds 100.4 degrees Fahrenheit, that’s a sign of an infection that you’ll probably need to take antibiotics for. Contact your doctor straight away.

The same applies if you notice a fluctuant mass (a lump that feels soft, like it’s filled with liquid) in your breast. That may be a breast abscess, a sign of severe mastisis.

If your symptoms are less severe but don’t resolve in 24 hours, that also warrants a visit to your doctor.

Signs of thrush

Thrush is a fairly common fungal infection that can occur in the nipple or breast and may be passed on to your baby. Symptoms of thrush include: 15

• Long-lasting sore nipples
• Breast pain during or after feeding
• Changes in your nipple color or texture, such as flaky, cracked, or itchy skin
• White spots on your baby’s tongue, cheeks, or gums

If you have these symptoms, then unsurprisingly, you’ll need to see your doctor quickly.

Make sure you bring your baby with you to get evaluated for thrush. You may both need treatment to avoid reinfecting each other.

The timeline for when milk comes in varies somewhat from mom to mom. Be patient—this part of motherhood sometimes takes a little time to get the hang of, but once you do, it’ll be one of the things you remember most from these early days of pregnancy.