Breast Changes During Pregnancy

Kathleen Tackett's picture


Dear Lactation Consultant,
It's been 6 years since I had my first child. I am now pregnant with the second. About how far into pregnancy are you when you start to have the oil come out of your breast pores?



Hi Lisa,
I assume that you are referring to the fluid (colostrum) that comes out of the tiny pores on the nipple itself. There is also a an antibacterial lubricant that is secreted by the little bumps on the areola (called Montgomery's Glands) that keep the area clean. This fluid is not visible, but it's there from early in the pregnancy, and you don't want to wash it off with soap.

Colostrum is a very interesting substance. Your breasts begin producing it at some point during pregnancy, but there is no set time. Generally, by the middle or end of the second trimester, you can express some drops -- but not always. Some women never see or are able to express any colostrum, while others leak so much that they have to wear pads to protect their clothes. The amount of colostrum you produce has nothing to do with the amount of milk you will produce for your baby once your milk comes in.

Colostrum is the first food available for babies immediately after birth and before your milk actually "comes in." It contains lots of antibodies and helps protect the vulnerable newborn from infection by coating his intestines and protecting him from viruses and bacteria. It also has a laxative effect, which helps him excrete meconium (the black tarry fetal stool he is born with) reducing the incidence of jaundice. It contains growth factors that help prepare his digestive system for absorbing and digesting milk. It is very easy for the newborn baby to digest, and is exactly what he needs to eat during the first days after birth. Colostrum is different from mature milk in other ways as well. It contains more salt and protein, and less sugar and fat then mature milk. It even looks different. It is ranges in appearance from clear and watery to thick, yellowish and sticky.

Some expectant mothers find that they leak lots of colostrum during pregnancy, while others are able to express only a drop or two. The amount of colostrum produced prenatally has no relationship to the amount of milk the mother will produce later on. Colostrum is very concentrated, and the volume produced is very small. Most mothers will have teaspoons rather than ounces. During the first 24 hours after birth, an average of 37 ml of colostrum is produced (an ounce contains 30 ml). Babies take in an average of 7-14 ml at each feeding.

When the mother's milk comes in a few days after birth, it is called "transitional milk." This mixture of colostrum and mature milk is produced from 4-10 days after birth. As the volume of milk increases, the protein content decreases and the amount of sugar and fat increase. Transitional milk may look yellowish due to the colostrum content. After 10-14 days, mature milk is produced. It still contains lots of valuable antibodies and immune factors, but no more colostrum. That's one reason that early breastfeeding is so important. Even if a mother nurses her baby for only a short time after birth, she is giving her newborn a precious gift that won't be available to him later on.

I hope this answers your question. I'm sure that everything will be just fine this time around, but if you have any questions, please let me know.

-- Anne, IBCLC