What a blocked milk duct is
A blocked milk duct means that milk drains less well from a specific area of the breast. You often feel a hard, tender spot or a lump, sometimes with slight redness. It often starts on one side and feels particularly uncomfortable when breastfeeding or expressing.
Important: a blocked milk duct is not automatically an infection. Often it is initially a mechanical problem of drainage, swelling and pressure in the tissue. This can develop into inflammation, and in some cases a bacterial mastitis. Clinical guidance therefore often refers to a mastitis spectrum. Academy of Breastfeeding Medicine: Protocol 36, Mastitis Spectrum
Typical causes and triggers
A blocked milk duct rarely has a single cause. It is often a combination of more milk than drainage, external pressure and a breastfeeding rhythm that does not fit at the moment.
- Unusually long gaps between breastfeeding or expressing
- Sudden changes in daily routine, less sleep, stress, travel
- Pressure on the breast from a tight bra, shoulder strap, prone sleeping or an unfavourable sleeping position
- Sore nipples or latching problems leading to ineffective emptying
- Too much or too vigorous pumping, which can increase tissue swelling
- Rapid reduction of feeds during weaning
How to recognise and assess a blocked milk duct
A blocked milk duct is usually localised. You have a clear point of pain or a lump but do not otherwise feel severely unwell. A mildly raised temperature can occur, but high fever and pronounced illness are more typical for mastitis.
More likely a blocked duct
- Localised lump or hard area
- Pain mainly with pressure, movement or during feeding
- No pronounced feeling of illness
- It improves noticeably within 12 to 24 hours with appropriate measures
More likely warning signs for mastitis
- Fever that persists or rises
- Shivering, body aches, marked illness
- Increasing redness and warmth spreading over the breast
- Rapid worsening instead of slow improvement
If you feel systemically unwell, the threshold for assessment is low. Guidance on mastitis symptoms frequently emphasises that breastfeeding should generally continue while the cause is treated. Patient information: mastitis
Blocked duct — what to do: measures that really help
The goal is not to force all milk out. The goal is to reduce swelling, improve drainage and avoid overstimulation. Many escalations happen because people become too aggressive under stress.
1) Continue to empty, but physiologically
Breastfeeding or expressing helps because it maintains drainage. At the same time, very frequent or intense pumping can further irritate the breast. A good principle is: regular and gentle, not maximal and frantic.
- Continue breastfeeding on demand without extra marathon sessions
- If you pump, use moderate suction and realistic intervals
- If breastfeeding is very painful, changing position can shift the pressure point
2) Cooling or warmth
This is the most common question. Swelling is a major part of the problem in a blocked duct. Cooling between feeds can reduce swelling and ease pain. Heat can be briefly comfortable immediately before feeding if it helps you relax, but prolonged heat can increase swelling.
- Cooling: between feeds, short and repeatable, if it helps you
- Warmth: rather briefly before feeding if it facilitates emptying
- If heat increases pressure afterwards, that is a sign cooling is more suitable
3) Gentle massage instead of deep kneading
Many people push hard on the lump. That can irritate the tissue. Often more helpful is a gentle, superficial motion that supports swelling reduction toward the lymphatic drainage, rather than pressing deeply on the painful spot.
4) Reduce external pressure
An underrated step is to remove anything that adds compression to the area. A too-tight bra, a hard underwire, shoulder straps or constant pressure when lying down can keep the blockage going.
5) Realistically manage pain and inflammation
If you have severe pain, this is not a test of will. Anti-inflammatory measures can help because less swelling often means less blockage. What suits you depends on your situation, including breastfeeding, medical history and other medications. If uncertain, consult a doctor or pharmacist for advice.
Blocked duct during weaning or when you want to breastfeed less
During weaning, a blocked duct often occurs because production reduces more slowly than you cut feeds. The common mistake is either persisting too rigidly or expressing too much. Both can prolong the problem.
A pragmatic approach is gradual reduction: empty enough so that pressure falls, but not so much that the body interprets it as a signal to produce more. If you are actively weaning and repeatedly get blockages, it is worth making smaller steps and avoiding abrupt changes in intervals.
When you should get it checked
Many blocked ducts improve noticeably within 24 hours. Assessment becomes appropriate if the course does not follow this pattern or if warning signs appear.
Get assessed if
- The area does not improve after 24 to 48 hours despite measures
- You develop a fever or feel clearly unwell
- Redness spreads or the pain increases markedly
- You notice pus-like discharge or the breast becomes extremely tender to pressure
- You repeatedly get blocked ducts in a very short time
Antibiotics and mastitis
Antibiotics are not the standard solution for every blocked duct. They are mainly considered when bacterial mastitis is likely or when the clinical picture clearly worsens. If antibiotics are prescribed, the aim is to treat the infection while continuing to allow milk flow, not to stop breastfeeding abruptly.
Common mistakes that can prolong a blocked duct
- Too aggressive massage, strong pressing or kneading of the lump
- Continuous heat that increases swelling
- Overpumping out of fear, which can further drive production
- Too tight clothing or persistent pressure on the area
- Weaning in one large step instead of gradual reductions
If you notice you are going in circles, a breastfeeding counsellor or medical assessment is often faster than trying another new trick.
Conclusion
Blocked milk ducts are common, painful and usually manageable if you reduce swelling, empty gently and avoid overstimulation. Cooling between feeds, physiological breastfeeding or expressing and reducing external pressure are the most effective steps for many people. If fever, marked illness or rapid worsening occur, seek assessment to rule out progression to mastitis.
