Black scabs on breasts in late pregnancy may be caused by physiological factors such as exuberant sebaceous gland secretion and breast milk, or it may be caused by nipple eczema and mammary gland trauma. 1. Physiological factors: the sebaceous glands in the body of women after late pregnancy secretion, the mammary gland part of the oil secretion will increase, if the breast part of the dirt and oil combination will appear nipple black scab performance. In addition, some pregnant women in late pregnancy will appear milk secretion, if the breast milk and breast parts of the combination of dirt, will also be manifested as breast black scab. 2. Breast eczema: Nipple eczema is considered to be caused by mental stress, heredity and breast milk stimulation. Women with breast eczema in late pregnancy will have small papules, itching, small blisters, vesicles, oozing, etc. If the oozing liquid from the nipple area combines with local dirt, the symptom of black scabs on the breast area will appear. 3. Mammary gland trauma: black scabs will appear during the healing of wounds after trauma to the breast area in late pregnancy. In addition, breast tumors and mastitis and other reasons may also appear in late pregnancy on the breast of the phenomenon of black scabs, if the physiological factors lead to late pregnancy on the breast of black scabs, do not need to treat, generally keep the local clean black scabs will disappear naturally. If it is a disease that leads to the appearance of black scabs on the breasts, then you need to consult a doctor in time, and you need to choose the appropriate measures for treatment under the guidance of the doctor.