When the normal connections between one area and another are cut or disturbed, the contents inside will divert someplace else. With a milk duct fistula -- also called a mammary duct fistula -- something -- a prior or recent surgery, usually, for anything from a biopsy to drainage of a breast abscess -- disrupts the flow of milk from the ducts to the nipple. Milk may discharge instead from an opening in the skin. You can usually continue to breastfeed with a milk duct fistula, but talk to your doctor about the best treatment in your case.
Milk duct fistulas can develop in several ways. If you've had breast surgery, such as breast reduction, augmentation or biopsy, the duct may have been cut in a way that interferes with milk flow. You might not realize this until you start nursing. If you develop a plugged milk duct while nursing, it can lead to an infection called mastitis, which can in turn develop into an abscess. An abscess is described as a walled-off infection that antibiotics have difficulty penetrating, and in this case, the abscess -- or the process of draining it -- can disrupt the milk duct, causing a fistula to form. Continue nursing if you develop blocked milk ducts or mastitis; offer the affected breast first, to make sure you empty the breast, the Better Health website advises. Stopping nursing increases the risk that an abscess that could lead to a fistula will develop.
If you have a milk duct fistula, some milk will leak out of an opening in the skin on the breast rather than out of the nipple, usually in an area around the areola. Since the breast contains more than one milk duct to carry milk from the milk-producing glands to the nipple, you will still have milk for your baby to suckle from the nipple as well. If you have an abscess drained, the leakage will most likely occur in the vicinity of the drainage incision.
In most cases, having a milk duct fistula doesn't decrease your ability to breastfeed your baby, since other ducts will continue to deliver milk to the nipple. However, the leaking can become an annoyance. While the fistula will heal in some cases, in others, only stopping nursing and suppressing milk production will stop the leaking. If a nursing mother has recently had surgery, such as abscess removal or biopsy, she might have to stop nursing on that side temporarily, international board certified lactation consultant Debbie Shinskie states in "The Pocket Guide to Counseling the Nursing Mother," but ask your doctor.
Treatment and Research
Surgical removal of the damaged duct, called a fistulectomy, will clear up the leakage and allow your skin to heal. In a British study published in the January 2006 issue of "World Journal of Surgery," 90 percent of women who had a fistulectomy noticed a distortion in the appearance of the nipple post-surgery. Smokers had a higher incidence of forming milk duct fistulas, according to the study; 83 percent of the women studied were smokers.