When Does Your Milk Supply Come In During Pregnancy?

I will never forget waking up at one point during my pregnancy and realizing my shirt was soaking wet. After looking for the cup of water I was sure I fell asleep with, I realized that the wetness happened because my body is in fact a wonderland and it was leaking milk all over the place while I slept. But did that mean my milk was already in? Did it mean I was going to have a healthy supply? When does milk supply come in during pregnancy anyway?

Although it can be incredibly weird to see your body manage something you've only ever read about, it's still pretty cool. But the interesting thing is that the milk you're leaking during pregnancy actually isn't milk at all. According to What to Expect, the fluid your breasts leak while you're pregnant is called colostrum, and it is a thin, yellowish fluid that contains more protein but less fat and sugar than your actual breast milk. It is the food your baby will eat for the first couple of days until your breast milk comes in.

So when does your body start producing this colostrum while you're pregnant? KellyMom noted that milk production usually begins at the midpoint of your pregnancy, around 16 to 22 weeks. According to The Bump, this second trimester milk production is due to the increased levels of hormone stimulating the production of milk in your mammary glands and the growth of milk ducts.

But if your breasts aren't leaking during pregnancy and you don't see any signs of colostrum, don't panic. The Bump noted that some women leak and some women don't, but that neither situation is indicative of your future milk supply or success with breastfeeding. International Board Certified Lactation Consultant Lisa Fortin told Romper that most healthy women who carry a baby to term are able to produce enough milk, so don't feel like you have to get a head start by pumping the colostrum you're producing while pregnant.