- Nipple discharge is a normal and expected part of pregnancy and breastfeeding.
- But it could also indicate an infection, breast cancer, or another type of tumor.
Nipple discharge is very common — up to 80% of women experience it at some point.
It is often a harmless symptom caused by breastfeeding or pregnancy. But in some cases, it can be a sign of something more serious like an infection or cancer.
Here are six reasons you might be having nipple discharge and when you should see a doctor.
1. Pregnancy
"Sometimes during pregnancy, especially the third trimester, the breasts may start producing milk," says Dr. Jennifer Wider, a women's health expert.
Colostrum, the first stage of breast milk, is what will normally leak out. "It can appear clear and thin, but may also appear thicker and yellowish," Wider says.
This is a normal part of pregnancy and generally isn't anything to worry about — but if you have any concerns, you can always check in with your doctor.
2. Breastfeeding
Breastfeeding can be tough on your nipples — they may become chapped, infected or injured during the process.
This means that you may have brief episodes of bloody nipple discharge in between feedings, says Dr. Maggie DiNome, a breast surgeon and professor at Duke University.
It's also normal for your breasts to occasionally produce milk after you've stopped breastfeeding. "Lactation can continue for several months after breast-feeding," DiNome says.
3. Breast cancer
"Breast cancer can cause nipple discharge if the cancerous cells involve the breast ducts near the nipple," DiNome says.
Unlike with lactation, breast cancer causes discharge to come from only one breast, Wider says.
There are two main types of breast cancer that can cause nipple discharge:
- Ductal carcinoma occurs when a tumor grows in the milk ducts of the breasts. This can cause a bloody or milky-white discharge, thickened, puckered skin, or a breast lump.
- Paget's disease of the nipple is a type of cancer that grows just behind the nipple. This can cause bloody discharge. Paget's disease can also cause a red, scaly rash on the nipple that may bleed or scab over. In some cases, you may also feel a lump behind your nipple.
If you have any of these symptoms, it's important to see your doctor as soon as possible.
Your doctor can perform scans or biopsies and determine the best treatment for you. As with most cancers, your treatment may include surgery, chemotherapy, or radiation.
4. Breast injury
"Breast injury can cause nipple discharge if it leads to internal bleeding in the area of the breast beneath the nipple," DiNome says.
This can happen if your breast is hit during an activity like sports, or if a partner stimulates your nipples too roughly.
"The discharge could be bloody, white, yellow, or clear," Wider says. You may also see other symptoms of injury like redness or bruising.
Most breast injuries heal in a few days — but if you have severe symptoms or your symptoms aren't going away, it's best to see your doctor.
5. A tumor
Nipple discharge can also happen if you have high levels of prolactin, the main hormone responsible for breast milk production.
Prolactin is secreted by the pituitary gland, a small gland at the base of your brain.
Your pituitary gland bumps up your prolactin levels when you need to breastfeed, but it may also activate if you have a tumor pressing against the gland.
This type of tumor, called a prolactinoma, is the most common cause of unusually high prolactin, "but certain medications can also elevate prolactin levels," DiNome says.
This spike in prolactin can cause milky discharge from your nipple.
Prolactinoma isn't cancerous or life threatening, but it can cause complications like infertility or vision loss.
Some other symptoms of prolactinoma include:
- Irregular or missed periods
- Vaginal dryness
- Acne
- Excessive body and facial hair
If you're experiencing these symptoms, see your doctor as soon as possible. Your doctor can offer treatments like surgery or medications to shrink the tumor.
6. Infection
"Infections in the breast can cause discharge if the infection involves the ducts near the nipple," DiNome says. This can happen when bacteria enter the skin on your breast.
"This will typically show up as a creamy whitish discharge," DiNome says.
The most common cause of infection is breastfeeding, but it can also be caused by:
- Eczema or other conditions that cause cracked skin
- Breast implants
- Nipple piercing
- Small cuts from shaving or plucking chest hairs
Some of the other telltale signs that you have an infection are:
- Swollen, tender breast
- Breast feeling hot to the touch
- Fever or chills
- Nausea and vomiting
- Fatigue
If you have symptoms of an infection, it's important to get medical attention right away. In some cases, your doctor will need to prescribe antibiotics.
Insider's takeaway
In many cases, nipple discharge isn't a cause for concern, but it can be a sign of more serious conditions like breast cancer or an infection.
DiNome advises that as a general rule, you should be concerned if the nipple discharge:
- Comes out without you squeezing the nipple
- Comes from only one breast
- Is bloody or clear
- Comes with infection symptoms like redness, swelling, or fever
"Don't hesitate to see a doctor, especially if you experience nipple discharge and you are not pregnant or breastfeeding," Wider says.