The causes of fleshy bumps under the armpits after childbirth are parametrium, swollen lymph nodes in the armpits, and fibroids in the skin of the armpits, as follows: 1. Parametrium: Parametrium refers to the appearance of excess breast tissue outside a pair of normal breast tissue, mostly seen in the armpits, mainly caused by malformations in the development of breast tissue, which generally does not need to be treated, but requires regular auxiliary examination, because parametrium has the risk of malignant breast cancer. 2. Swollen armpits Lymph nodes: Due to the postpartum mammary ducts are not smooth, causing bacterial growth and mastitis, this will lead to swollen axillary lymph nodes, so in terms of treatment, you can apply hot compresses locally and keep regular breastfeeding to make the mammary ducts smooth, and in serious cases, you can also take oral roxithromycin capsules. 3.Fibroma of axillary skin: It is mainly a benign tumor due to excessive proliferation of fibrous tissues in the axillary skin, at this time It can be surgically removed under the guidance of a dermatologist, and can also be observed regularly. Therefore, for postpartum fleshy bumps under the armpit, you can go to the dermatology office for the corresponding treatment.