When Do You Start Leaking Breast Milk During Pregnancy? Experts Say Your Boobs Are Already Preparing


Before having children, I naively assumed that the only thing to really change about a woman's body during pregnancy was the growth of her stomach. (Ignorance is bliss.) But now, after three pregnancies, I've seen my body do wackier things than I imagined. It's constantly a guessing game when you're growing a baby: you just don't know what your mom bod will do next. If this is your first, you're likely wondering about the phenomenon that is your now-ample breasts producing milk — and might be considering some nursing pads. But when do you start leaking breast milk during pregnancy? Well, let's back the train up first.

Leigh Anne O'Connor, International Board Certified Lactation Consultant, tells Romper that what you're probably thinking about is colostrum, not actual breast milk. "The breasts start making colostrum about halfway through the pregnancy, between 16 and 22 weeks," she says. "Some people leak colostrum during pregnancy and some do not."

If you're more than halfway through your pregnancy and haven't seen any colostrum leak, you might wonder whether your body is actually producing any. There's nothing to worry about if you haven't seen a trace, but if you're curious, you can try hand expressing some while standing in a warm shower. There's something pretty cool about seeing your body actually preparing to sustain this little life when she emerges.


If all goes well with your delivery, your baby will likely want to nurse pretty soon after birth, and the nurses or midwives present can coach you on proper positioning and getting a good latch. At this time, it is almost definitely colostrum that your baby will be getting. And despite what you might think due to the scant amount, this is no second class beverage. Colostrum is thick and nutrient-dense and has been hailed by some as "baby's first superfood," according to Parents.

The low volume of colostrum you produce might concern you, but it really is enough to nourish your baby in the beginning. Natalie Telyatnikov, founder of Better Postpartum, explains to Romper that on the day they are born, a baby's stomach can only hold a few milliliters of liquid. The stomach grows quickly, but even still, at 3 days old it's only the size of a marble, and by day 5, a ping pong ball. So it doesn't need much liquid to feel full.

In most women, colostrum changes to breast milk between two to four days after the baby is born, at which point your breasts will become engorged. Some women do experience their milk coming in before birth, O'Connor says, but those cases are rare.


Although it is atypical, leaking breasts can begin as early as the first trimester, says Orange County Nurse Practitioner Patricia Evans. Most women will not experience it until later, if at all, but seeing some lactation in the first 12 weeks gestation is not cause for alarm. Evans tells Romper that you should never try to pump colostrum during pregnancy, because it can cause contractions that send you into preterm labor.

Experts say that hand expression is safe to do after 37 weeks, however. Telyatnikov tells Romper that at this point "colostrum harvesting" can be done to help supplement breastfeeding later. "Women can store small droppers of saved colostrum in zip lock bags in the freezer, and later defrost them in the refrigerator or at room temperature once baby has arrived."

Telyatnikov explains that previously extracted colostrum can be used to give a mother's nipples a rest between feedings to help heal nipple damage, too. She also points out that a stored supply comes in handy if the baby has an improper latch and needs to be fed through syringes while learning how to feed from the breast. Colostrum might not look like much, but it's not called "liquid gold" for nothing.