What a blocked milk duct is
A blocked milk duct means that milk is not flowing well from an 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 during breastfeeding or pumping.
Important: a blocked milk duct is not automatically an infection. Often it is initially a mechanical issue of impaired drainage, swelling and tissue pressure. This can develop into inflammation, and in some cases into 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 can drain, external pressure and a breastfeeding rhythm that doesn’t fit right at the moment.
- Unusually long gaps between feeds or pumping
- Sudden changes in routine, reduced sleep, stress, travel
- Pressure on the breast from a tight bra, shoulder strap, lying on the stomach or an unfavourable sleeping position
- Sore nipples or poor latch, causing ineffective emptying
- Too much or too strong pumping, which can increase tissue swelling
- Rapid reduction of feeds when weaning
How to recognise and assess a blocked milk duct
A blocked milk duct is usually local. You have a clear point of pain or a lump, but otherwise do not feel seriously unwell. A mildly raised temperature can occur, but high fever and marked malaise are more consistent with mastitis.
More likely a blocked duct
- Local lump or hard area
- Pain mainly with pressure, movement or during feeding
- No pronounced general illness
- It improves noticeably within 12 to 24 hours with appropriate measures
More likely signs of mastitis
- Fever that persists or rises
- Chills, muscle aches, pronounced malaise
- Increasing redness and warmth that spreads
- Rapid worsening instead of gradual improvement
If you feel systemically unwell, the threshold for assessment should be low. Guidance on mastitis symptoms often emphasises that breastfeeding is usually continued while the underlying cause is treated. NHS: Mastitis
Blocked milk duct — what to do: measures that really help
The goal is not to force all milk out. The aim is to reduce swelling, improve drainage and avoid overstimulation. Many escalations happen because people respond too aggressively in a stressed state.
1) Continue emptying, but in a physiological way
Breastfeeding or pumping helps because it maintains drainage. At the same time, very frequent or very strong 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) Cold or warm therapy
This is the most common question. In a blocked duct, swelling is a major part of the problem. Cooling between feeds can reduce swelling and ease pain. Warmth can be briefly pleasant before feeding if it relaxes you, but prolonged warmth can increase swelling.
- Cool: between feeds, briefly and repeatable, if it helps you
- Warm: rather short-term before feeding if it helps with milk removal
- If warmth increases pressure, that is a sign that cooling usually works better
3) Gentle massage instead of deep kneading
Many people try to force the lump away. That can irritate the tissue. More helpful is often a gentle, superficial movement that supports swelling reduction toward lymphatic drainage, rather than pressing deeply on the painful point.
4) Reduce external pressure
An underrated step is removing anything that adds compression to the area. A too-tight bra, a firm underwire, shoulder straps or persistent pressure while lying can keep the blockage going.
5) Manage pain and inflammation realistically
If you have severe pain, this is not a character test. Anti-inflammatory measures can help because less swelling often means less blockage. What suits you depends on your situation, including breastfeeding, pre-existing conditions and other medications. If unsure, seek advice from a medical clinic or pharmacist.
Blocked milk duct during weaning or when you want to feed less
During weaning, blocked ducts often occur because production reduces more slowly than drain. The most common mistake is either persisting too harshly or pumping too much. Both can prolong the problem.
A pragmatic approach is gradual reduction: remove just enough milk that pressure decreases, but not so much that the body receives a signal to increase production. If you are actively weaning and repeatedly get blockages, it is worth reducing the steps and avoiding abrupt changes.
When you should get it checked
Many blocked ducts improve noticeably within 24 hours. Assessment is sensible if the course does not follow that direction or if warning signs appear.
Seek assessment if
- The area does not improve after 24 to 48 hours despite measures
- You develop a fever or feel clearly unwell
- Redness spreads or pain increases markedly
- You notice pus-like discharge or the breast becomes extremely tender to pressure
- You get repeated blocked ducts in a very short time
Antibiotics and mastitis
Antibiotics are not the standard solution for every blocked duct. They are considered mainly when bacterial mastitis is likely or when the condition clearly worsens. When antibiotics are prescribed, the aim is to treat the infection while continuing milk removal rather than stopping breastfeeding abruptly.
Common mistakes that can prolong a blocked duct
- Too aggressive massage, strong pressing or kneading on the lump
- Prolonged warmth that increases swelling
- Over-pumping out of fear, which can further drive production
- Tight clothing or persistent pressure on the area
- Weaning in a big jump instead of small reduction steps
If you notice you are going in circles, lactation support or a medical assessment is often faster than trying another 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 pumping and less external pressure are the most effective steps for many. If fever, marked illness or rapid worsening occur, it should be checked to rule out mastitis.
