What Causes Clogged Milk Duct?

It is only natural that after birth, you will be breastfeeding or pumping milk for your young one to feed on. The let-down reflex in the breasts is what triggers the milk to be released and flow through the milk ducts to the nipples. This reflex is as a result of the hormone oxytocin, which is released from the brain. If the breastfeeding mother has a clogged milk duct, the amount of milk released flows out at a slower rate than normal. There are many factors which can contribute to clogging of the milk ducts including internal factors such as back flow of milk in the ducts and external factors such as pressure from wearing tight clothes. A clogged milk duct is not a complicated medical issue, but still one needs to have it cleared out before it develops into an infection i.e. mastitis. Nevertheless, clogged milk ducts cause a lot of discomfort for the mother, especially when feeding and they’re also painful.

What Causes Clogged Milk Duct?

What are the possible causes of a clogged milk duct? A clogged milk duct is related to poor let-down of milk from the mammary glands to the nipples. There are several contributing factors which can lead to a clogged milk duct by acting as an obstruction in the duct. It does not necessarily have to be a physical obstruction, but clogged milk ducts are characterized by lumps in the breast. The lumps are usually as a result of swelling of the breast tissues near the obstruction. The possible causes of clogged milk duct include:

  • Breastfeeding on a schedule instead of on demand. During the first weeks after giving birth, your baby will want to breast frequently. It is important that if they want to feed, you do so rather than feeding when you want to do so.
  • Long intervals between breastfeeding sessions or skipped sessions. This often arises when the baby sleeps for long hours, thus you are not breastfeeding regularly despite having enough milk supply to feed him/her.
  • Mothers who have plenty of milk i.e. those with an oversupply of milk are also at a greater risk of developing a clogged milk duct. Every woman produces certain levels of breast milk, and others have more than others. So, if a woman has an oversupply yet the baby is not draining all the milk, then a milk duct could get clogged.
  • Wearing tight, poorly fitting clothes such as bras and tops could lead to a clogged milk duct. The tight clothes press on the breast thus causing compressions, which could easily cause an obstruction in the breast.
  • Hurried feedings. Babies will normally feed slowly in the beginning and with time, their pace will pick up. Therefore as the mother, you need to adapt to the baby’s rate of feeding and not rush it as it could cause problems for you in terms of clogged milk ducts.

  • Latching problems. This could be seen as the general problem when the baby doesn’t feed properly or isn’t breastfeeding as often as expected. For example, the baby might not be able to suckle properly or the milk isn’t flowing normally, and thus they feed with problems.
  • Poor positioning of the baby while breastfeeding. This might seem insignificant, but if you do put into consideration how you position your baby during feeding, it could be a cause of blockage in the milk duct. It could be that the baby is pressing on the breast during feeding or you as the mother is pressing the breast so as to accommodate for the baby’s nostril, hence putting pressure on it.
  • Clogged milk ducts could also be as a result of a breast infection (mastitis), nipple piercings and scarred/bruised nipples or breast injury, breast cancer, and breast surgery.

  • Stress is also a contributing factor to a clogged milk duct, whether physical or mental. If you have mental stress, it will interfere with milk release traced back to the hormone oxytocin. Physical stress such as vigorous upper arm exercises could also cause breastfeeding problems for the mother as it strains the breast muscles.


Clogged milk ducts can arise from various factors. The best thing with a clogged milk duct is that it can easily be cleared at home within a day or two. If you can prevent yourself from some of the contributing factors, ensure you avoid them at all cost for your own sake and that of the baby as well. The best way to unblock a clogged milk duct is feeding regularly and always starting a feeding session with the affected breast side. In addition to that, you can use warm compressors or take a warm shower before breastfeeding to enhance milk flow.

Also Read:

Pramod Kerkar, M.D., FFARCSI, DA
Pramod Kerkar, M.D., FFARCSI, DA
Written, Edited or Reviewed By: Pramod Kerkar, M.D., FFARCSI, DA Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:November 29, 2018

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