Which of the following is a risk factor for developing mastitis in nursing mothers?

Cracked and bleeding nipples are a significant risk factor for developing mastitis in nursing mothers. When the skin on the nipple becomes damaged, it creates an entry point for bacteria, which can lead to an infection in the breast tissue. Mastitis is often characterized by inflammation, swelling, and infection, and damaged skin increases the likelihood of bacteria penetrating into the breast. As breastfeeding continues, the trauma to the nipple can lead to further complications, including pain, engorgement, and more severe cases of mastitis.

In contrast, frequent breastfeeding and regular breast emptying actually work to prevent conditions that might lead to mastitis. These practices help ensure that milk is adequately removed from the breast, decreasing engorgement and reducing the risk of infection. The use of supportive bras is generally beneficial for comfort and proper support during nursing, and does not typically contribute to the risk of developing mastitis when used appropriately.