Inclusion Criteria:  primparious women; full-term delivery; age ≤35; breastfeeding within 7 days after delivery; with autonomous behavior ability; provide voluntary informed consent; • ability to breastfeed individually; prenatal breast ultrasound shows no breast lesions.  Exclusion Criteria:  abnormal breast or nipple development (Poland syndrome or degree II and above inverted nipple); istory of breast surgery; history of chest radiotherapy; history of malignant tumors; history of mastitis; severe cardiovascular and cerebrovascular diseases, chronic diseases (Ecog score >3, long-term medication affects breastfeeding); skin diseases or connective tissue diseases; Hepatitis, syphilis, gonorrhea, AIDS and other infectious diseases.