During breastfeeding, you may find a lump in your breast and be concerned about what it means. In people who aren’t breastfeeding, lumps can be possible signs of breast cancer. But during breastfeeding, lumps and other breast changes are most often totally normal.

Keep reading to discover when to worry about lumps while breastfeeding. You’ll also learn about several benign (noncancerous) breast conditions that can cause breast lumps.

Breast Cancer While Breastfeeding

Devloping breast cancer while breastfeeding is uncommon. Just 1 in 3,000 women will develop breast cancer during lactation or pregnancy, according to a 2023 study in the International Journal of Surgery Case Reports.

If breast cancer is diagnosed during the first year after childbirth, including while you are breastfeeding, it is considered pregnancy-associated breast cancer.

Being at a younger age reduces the risk of breast cancer — researchers reported 5 percent to 7 percent of breast cancer cases occur in women under 40. However, it doesn’t eliminate the risk and you have to be aware of any change in your breasts.

While postpartum breast cancer or lactation-associated breast cancer is rare, it can happen. Any lump that doesn’t improve (or keeps getting bigger) should be checked by an oncologist.

Cysts During Breastfeeding

Pregnancy and breastfeeding cause many physiological changes to your body. This includes making your breasts bigger, firmer, and denser.

It’s common for nursing mothers to notice more lumps in dense tissue due to milk production or potentially blocked ducts. Rarely are these lumps a sign of breast cancer.

If you find a lump in your breast during breastfeeding, it could be a cyst called a galactocele. Galactoceles are usually painless, but they can lead to infections if untreated. These milk-filled glands may fluctuate in size and develop when a blocked milk duct causes milk to build up in the breast.

Treating Cysts

Galactoceles are diagnosed with an ultrasound. Observation is the most common initial management strategy for asymptomatic cysts, as many resolve on their own after breastfeeding ends. If necessary, the blockage can be drained using a needle or removed with surgery.

Mastitis

Lumps in the breast can also be a sign of inflammation in the breast known as mastitis. Hard lumps or lumps that cause breast pain are often a symptom of this condition. The inflammation can also cause flu-like symptoms, such as achiness, exhaustion, and fever.

Mastitis can happen when milk ducts are blocked or when you experience engorgement, when your breasts become full with milk and swell. The affected area on your breast may become discolored, although skin changes don’t always occur.

In some mastitis cases, a pocket full of pus called an abscess may form. An abscess is diagnosed with an ultrasound. Just like a cyst, a breast abscess can be drained by a physician with a needle aspiration, if necessary, or by surgical drainage if the purulent fluid is too thick.

Treating Mastitis

Mastitis is usually first treated with ice or cold packs to reduce inflammation. Your doctor may suggest using an over-the-counter medication like acetaminophen or a nonsteroidal anti-inflammatory drug (NSAID) like ibuprofen. Always ask your doctor before taking any over-the-counter medication while breastfeeding.

Warm compresses may work for some people to ease symptoms.

If the symptoms continue, your doctor may prescribe antibiotics to treat the breast infection. If you’re prescribed antibiotics, make sure you take the full course of doses to prevent the infection from returning.

Don’t stop breastfeeding on the affected side if you have mastitis. Ensuring a consistent milk flow actually helps to clear the infection and promote proper drainage. Plus, healthy babies aren’t at risk from drinking breast milk during a mastitis episode. If you have extra milk after feeding, you can try expressing it by hand or with a breast pump.

Massage may also help. Avoid deep or forceful massage and instead try gentle, light sweeping motions to increase your comfort and encourage lymphatic drainage. Focus on making the feeding or pumping process comfortable rather than trying to “massage out” a clog.

Inflammatory Breast Cancer

Skin discoloration, bruising, and swelling in the affected breast are common symptoms of mastitis, but they can also be signs of a rare form of breast cancer called inflammatory breast cancer (IBC). This cancer usually develops within the milk ducts and then spreads throughout the breast.

IBC can lead to quick changes in the breast’s appearance, usually over a period of just a few weeks. These changes don’t improve with self-care measures or antibiotics, and the breast can develop orange peel skin (thickened skin with dimples around enlarged pores that resembles an orange peel).

Inflammatory breast cancer is rare, making up only 1 percent to 5 percent of breast cancer cases in the United States. If you’re breastfeeding, it’s much more likely that your symptoms are caused by mastitis, but if you are concerned, you can always ask your healthcare team.

Mammograms While Breastfeeding

If breast discoloration and swelling persist after antibiotic treatment for mastitis ends, your healthcare provider may suggest using imaging to look at your breast tissue.

For a new or persistent lump while breastfeeding, ultrasound is usually the first-line imaging tool. Your healthcare provider may order a mammogram or tomosynthesis screening (3D mammogram) depending on findings. This keeps the key steps to diagnosing the problem current and clear.

Although it’s more difficult to read a mammogram when breasts are producing milk, it can still be a useful tool, especially if your radiologist is familiar with reading images of a lactating breast. Breastfeeding or pumping right before the mammogram can help empty your breasts to produce a clearer image.

Depending on what the mammogram shows, your doctor may also order a biopsy to get more details about the lump.

Mammograms and biopsies don’t affect the milk supply, so it’s safe to feed your baby, or at least express the milk with a breast pump, after these procedures.

What To Do if You Find a Lump While Breastfeeding

If you notice a lump in your breast while breastfeeding, don’t panic. Most lumps in people who are breastfeeding are galactoceles or inflammation like mastitis. Depending on your symptoms, you might try basic treatments for mastitis, such as resting and applying ice packs to the tender areas.

Any lump that’s still there or larger after a week should be checked by a physician. In addition, if you have a fever or if you have serious concerns at any time, consult with your healthcare professional immediately.

If you see discoloration on your breast — such as red, purple, brown, or gray streaks — you should also seek medical advice immediately. This discoloration can be a sign of an infection that, if not treated, can turn into sepsis, a life-threatening condition.

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