Clogged Ducts and Mastitis: What really helps & what to stop doing

It's not a "clog" — it's swelling

For years, people were told a clogged duct is thick milk stuck inside, like a clog in a pipe. Newer research shows this usually isn't true. What's really happening is swelling inside the duct. The swelling makes the duct narrow, so milk can't flow through as easily. That's what causes the sore lump.

Think of it like a traffic jam. The road narrows, cars back up, and everything behind it slows down and gets sore. Your milk duct works the same way — the milk isn't "stuck," it's just slowed by the swelling around it.

What causes the swelling?

Research now points to a few main triggers:

• Too much milk supply (your body is making more than baby needs right now)

• A shift in the natural bacteria in your breast, which can trigger inflammation

• Milk sitting longer than usual (long stretches, skipped feeds/pumps)

• A pump flange that doesn't fit right, or too much pump/nipple shield use

• Tight clothing or a bra that presses on one spot

What does it feel like?

You might notice:

• A sore or tender spot in your breast

• A firm lump

• Warmth or slight redness

• More pain when your baby feeds or you pump

• Less milk flow from that side for a little while

If you also feel feverish, achy, or very tired, this could be mastitis. The good news: most mastitis starts the same way — as inflammation, not infection — so many of the same steps below help both.

What to do and what to skip

Do this	Skip this
Ice or a cold pack, 10–15 min at a time	Heat or warm compresses on the sore spot
Ibuprofen, if it's okay for you to take	Deep or hard massage
Gentle feeding or pumping as usual	Extra pumping to try to "empty" the breast
Light, gentle strokes toward your armpit	Vibrating tools or hard suction tricks
A soft, well-fitting, supportive bra	Epsom salt soaks
Rest and drink water	Pushing through pain to force milk out

The goal is to calm the swelling — not push milk through it.

What about mastitis?

If swelling turns into mastitis, the same conservative approach usually helps:

• Rest

• Ice

• Ibuprofen

• Gentle, regular feeding or pumping

Antibiotics are usually saved for when:

• Symptoms don't improve within 24 hours

• You see pus or unusual discharge

• You have a high fever or spreading redness

  
  

You can keep breastfeeding or pumping. Your milk stays safe for your baby.

When to reach out for help

Contact your lactation consultant or primary care physician if:

• This keeps happening in the same spot every time

• Symptoms don't improve in 24 hours

• You have a fever or feel worse, not better

• You're not sure what's causing it

• Pumping or latch doesn't feel right