By Ali Weatherford

I always hesitate a little to write about the more rare and strange conditions related to breastfeeding because I’d hate for people to think about these things when preparing to have a baby! They are really unusual and not worth worrying about. But on the other hand, it’s really good to have this kind of information so that you can have some peace of mind if something weird and benign does happen.

What color is milk supposed to be?

Breast milk can come in many colors. A lot of times, we have no idea what color it is because the baby takes it directly from the breast. But if you pump your milk, you’ll be able to see it in the bottle. It’s usually white or yellowish-white. Sometimes it could have a bluish tint when the milk is very thin. If you pump a lot, you might start to notice that the color changes. It can depend on the time of day, how long you pumped, whether your baby just fed from the breast before pumping, how fatty the breast milk is, and even what you eat!

Some foods, including natural fruits and vegetables, can color your breast milk. So can food and drinks that are artificially colored. It might be obvious if your milk looks green or orange. Did you eat a lot of spinach or carrots? Or maybe a lot of your favorite green gummy bears? But if you’re concerned about your pinkish or “rusty” colored milk, you might avoid eating artificially colored foods and see if it clears up quickly.

There are conditions that can cause there to be blood in the breast milk, which can also cause discoloration. These things can be totally harmless or might indicate that something is wrong. Rusty Pipes Syndrome (RPS) is a condition that can cause your milk to be discolored (usually brownish), but is totally benign.

What is RPS?

RPS is very rare, and the causes are still not clear. What they do know is that it’s not harmful. It doesn’t have to affect your breastfeeding plan or your baby. In fact, a lot of times people don’t even know it’s happening when they are exclusively directly breastfeeding and never actually see the milk.

Rusty Pipe Syndrome got the name because the milk might look like the water that comes out of a rusty pipe. The milk might look reddish or just kind of rusty or dirty. It is not caused by rusty pipes though! What they do know is that it’s a temporary issue and not harmful. It’s not caused by old or “rusty” milk ducts. It’s possibly caused by a little bit of blood leaking into the milk supply from broken or fragile blood vessels. Yes, blood! That might sound really scary, but it’s really OK.

It might start during pregnancy and continue for a while after, but it usually begins starts after the baby is borncomes, and it . It should go away after by a week or 10 days postpartum. There is a lot of change happening in the breasts during pregnancy and as a full milk supply develops in the first few days postpartum. It might just be that these changes in structure cause some irritation and a little bit of blood leaks into the milk supply. It is most often a very small amount of blood and not harmful at all.

How do I know I have it?

There can be other causes of bleeding, and other conditions are actually more likely than RPS. If you are pumping milk and notice a strange color like reddish, brownish, pinkish, or just sort of dirty, you should first see your doctor and a lactation consultant. Since there are other medical conditions that can cause this, it’s best to rule those things out first. If they can’t find any other causes, then you might have RPS. Some other signs that can help point to an RPS diagnosis include:

  • RPS usually goes away by 10 days postpartum.
  • If you can notice that the bloody milk is only coming from one pore, it’s probably not RPS.
  • RPS usually causes bleeding from both breasts. Other conditions are more likely to cause bleeding in just one breast.
  • RPS does not cause pain.
  • RPS may also occur again in other pregnancies.
  • RPS does not occur in the first trimester of pregnancy.

What else could it be?

There are other things that can cause blood in the breast milk or discolored milk. Some of these are:

  • Cracked and bleeding nipples. This is the most common cause of discolored milk, and can be caused by a bad latch or just some initial irritation as you and your baby are learning to breastfeed. This usually causes some pain as well.
  • Mastitis is another common cause. This is an infection in the breast, and often causes some soreness or tenderness and possibly even fever and illness. You might also notice redness or discoloration on the breast.
  • Less common is a condition called Papillomas. These are small growths in the milk ducts that can sometimes cause bleeding. They are also not harmful.
  • Breast cancer is a very rare cause of blood in breast milk, but it’s a good idea to rule it out. Some ways to do that are with regular self checks, regular annual exams with your doctor, basic breast cancer awareness, and a follow up with your doctor if you have blood in the breast milk.
  • There is a bacteria that can be found in breast milk. When you are directly feeding from the breast, it’s unlikely to cause a problem because there are only very small amounts. However, if you are pumping and bottle feeding, there is a higher risk of illness for the baby when they drink the stored milk because the bacteria can continue to grow there. So, if your milk is pink and you can rule out other causes, a test for bacteria might be necessary. This is very rare.

It’s highly unlikely that you’ll have blood in your breast milk, but in case it happens, it’s good to know that it’s most likely caused by something harmless and that you can continue to breastfeed your baby.


Our articles are not intended or implied to be a substitute for professional medical advice, diagnosis, or treatment.

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