After giving birth to her baby, Ms. Jiang found a walnut-sized lump in her left breast with slight pain, and thought it was a milk stagnation and didn’t pay much attention to it. 3 months later, Ms. Jiang found that the lump didn’t hurt anymore, but it didn’t get smaller. She was not sure whether this situation was good or bad, so she came to the breast department of Qin Maternity and Child Hospital. After examination, the doctor highly suspected that the lump on her breast was a malignant tumor, and she was diagnosed with breast cancer and given surgical treatment after a puncture biopsy. During the operation, it was found that there were lymph node metastases in the armpit. In fact, Ms. Jiang had felt a small lump on her breast before she was pregnant and went to the hospital, but she did not take any measures and delayed until she found a change in the lump when she was breastfeeding, which resulted in missing the best time for treatment. Seventy percent of pregnancy-related breast cancers occur in women under the age of 30, and although the incidence rate is low, the degree of malignancy is very high. The significant increase in hormone levels during pregnancy can help cancer cells to “grow like crazy”, so women who are planning to get pregnant should check their breasts first, and if there are lumps, they should identify the nature of the lumps and deal with them before getting pregnant. Young women who are planning to get pregnant must insist on breast self-examination before and during pregnancy. If you find any lumps in your breasts, especially painless ones, it is best to see a specialist for a detailed examination. Generally speaking, most of the lumps are benign and can be dealt with in an appropriate way. If the lumps are found to be malignant, it is recommended to receive regular treatment before carefully considering the issue of childbearing. At present, the incidence age of breast cancer is getting younger and younger, and early detection and early standardized treatment is the key to improve the prognosis of breast cancer. In addition to regular breast self-examination, it is best for women to undergo a specialist examination once a year to detect abnormalities and deal with them as soon as possible. Cases like Ms. Jiang are not uncommon, this type of pregnancy and lactation breast cancer patients often exist before pregnancy, some are found to pay no attention to, some although to the hospital but afraid of the impact of breastfeeding did not actively deal with, the study shows that this type of breast cancer malignant degree is high, easy to metastasize, the prognosis is relatively poor. Changes in hormone levels during pregnancy will promote the growth of breast cancer cells. Occurring in this special stage of pregnancy and breastfeeding, the physical and mental impact on women will be even greater, and it will bring more difficulties to the whole family, including the baby, and it should be highly valued by the expectant mothers.