You’re aware of so many of the changes that happen to your body during pregnancy —  the weight gain, the increased need to pee, the exhaustion, the aches and pains.

But there are others that happen without you even noticing, including your increased blood volume, cervical dilation and effacement (or thinning) as your due date nears, and the production of colostrum in your breasts in preparation for baby’s first meal.

What is colostrum?

Colostrum, dubbed liquid gold because of its incredible antibody and nutrient content, is the precursor to the breast milk that will very soon feed your bundle of joy.


Until then your baby will need just a few teaspoons of the antibody-rich colostrum per feeding for all her nourishment. And though it’ll seem like only a little colostrum is there, your breasts will be producing more than your little one will need to fill her tiny tummy.

Weirdest Pregnancy Symptoms

When do pregnant women start leaking breast milk?

Your body starts to produce colostrum in the first trimester, but moms-to-be usually don't start leaking breast milk until closer to the end of pregnancy, if it happens at all when they're pregnant.

Why are your breasts leaking during pregnancy?

Your breasts are leaking during pregnancy because prolactin, the hormone responsible for milk production after the birth of your baby, starts revving up while you're still pregnant, usually in the third trimester. 

In fact, your hormones are performing a delicate dance during pregnancy, working hard to stay in just the right balance so that everything — from when you go into labor to when milk production starts — should happen at the right time.

The reason breast milk isn’t produced in high quantities when you're expecting, especially earlier on in pregnancy, is because of the sky-high estrogen and progesterone levels that keep the milk-making in check.

If prolactin levels slightly outpace those of the estrogen and progesterone, colostrum can leak out a bit. It’s normal and nothing to worry about.

Also normal is to leak a little colostrum when your nipples rub against your bra during exercise, or when they’re stimulated in any way — such as during sex.

How can you tell if you have colostrum?

Check the inside of your bra — do you see any small yellow or orange stains? That’s a sign you’re making (and leaking) a little colostrum already.

Not noticing that telltale sign? No worries — you can try to express a few drops by gently squeezing your areola.

Still nothing? Still nothing to worry about. Your breasts will get into the milk-making business when the time is right and baby's doing the milking.

What can you do about colostrum and leaking breast milk during pregnancy?

If you’re leaking colostrum, it’s probably not more than a few drops. If the flow is more than you're comfortable with, wear nursing pads inside your bra to catch the overflow.

When to call the doctor

It’s a good idea to call the doctor if you notice a lot of leakage (more than a few drops) and/or if the colostrum is bloody.
