When To Expect Your Breast Milk To Come In

If you're expecting a baby and planning to nurse, you may not know that breastfeeding in the first hours after birth doesn't involve copious amounts of bottle-filling milk. Instead, you'll produce smaller amounts of two other types of breast milk before your mature milk actually comes in.

But the milk you produce in the first few days is still important to your baby. If you're wondering, "When does breast milk come in?" or what you can do if yours seems to be delayed, here's all you need to know.

Stages of Breast Milk

According to Taniqua Miller, M.D., an Atlanta-based OB-GYN, there are three stages of breast milk development that occur after birth: colostrum, transitional milk, and mature milk.


This is usually a thicker milk, often dark yellow in color, that provides your baby with protein and antibodies against infection. Interestingly, your colostrum has actually been in production since the second trimester of your pregnancy, says Abrie McCoy, certified lactation consultant (CLC) with SimpliFed. You won't make a lot of colostrum, but your baby doesn't need much in these first few days.

Transitional milk

About two to five days after giving birth, you can expect transitional milk. This is typically lighter and thinner than colostrum, notes Dr. Miller, and contains additional fat to sustain your baby until your mature milk comes in. It may last up to two weeks postpartum.

Mature milk

The final stage is mature milk, which is thinner than transitional milk, especially when it first comes out. Later, it may become creamier as the fat content increases toward the end of each feeding.

Signs Your Breast Milk Is Coming In

There are several signs that your milk is beginning to come in (aka turn into mature milk), most notably an increase in size, heaviness, or general fullness of the breasts.

"Birthing and nursing parents will know when the milk production is beginning often just by the sensations they experience," says Amanda P. Williams, M.D., MPH, medical director at Mahmee, a maternal health care company. "The changes in breast fullness can cause pressure and even pain for some moms, the breasts and nipples can feel warm and sensitive to the touch, and some women experience low-grade fever for 24 hours."

Additionally, notes Dr. Williams, you may notice that your milk is no longer coming out in drops but beginning to leak or even spray from the nipple when it's time for a feeding (and speaking of feedings, your breasts will feel heavy when they're full and empty after you've fed your baby).

You'll also probably notice a change in your baby, says Dr. Williams: "The most common indicator of milk flow changing and increasing from colostrum to mature milk is the number of wet and dirty diapers, and the ability of their infant to sleep for extended periods of time."

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