More and more women in our country are choosing to have children later in life, and the fertility of young patients who develop breast cancer will be affected by the course of breast cancer treatment if they have not yet had children, and there is still no effective method found to protect ovarian function. The 2015 NCCN treatment guidelines for breast cancer discuss fertility in young breast cancer patients, and there are some preliminary insights into this issue: 1. All premenopausal breast cancer patients should be informed of the potential effects of chemotherapy on fertility before receiving chemotherapy and be asked if they have any desire to become pregnant in the future, and if the patient has a desire to become pregnant in the future, they should consult a 2. Although patients may experience amenorrhea during or after chemotherapy, most patients younger than 35 years of age will resume menstruation within 2 years after the completion of adjuvant chemotherapy; 3. There is no necessary link between menstruation and fertility, and the absence of regular menstruation, especially if the patient has irregular menstruation during oral tamoxifen, does not necessarily indicate a lack of fertility, while the resumption of The absence of regular menstruation, especially irregular menstruation during oral tamoxifen, does not necessarily indicate a lack of fertility, nor does the resumption of menstruation indicate fertility. Although limited information is available, the use of hormone-containing contraceptives is not recommended as a contraceptive measure regardless of the hormone receptor status of breast cancer patients; 6. Recommended contraceptive measures include: intrauterine devices and other methods to prevent sperm-egg union 7. Randomized clinical trials have shown that the use of sex hormone-releasing hormone analogs (GnRH) to suppress ovarian function during adjuvant chemotherapy in premenopausal patients with estrogen-negative breast cancer can protect ovarian function and reduce the incidence of amenorrhea caused by chemotherapy drugs. Breast-conserving therapy is not a contraindication to breastfeeding afterwards, but the quality and quantity of milk produced by the preserved breast may be inadequate and may lack certain nutrients, and breastfeeding during chemotherapy and radiotherapy is not recommended; 9. There is less clinical data showing that the use of GnRH in estrogen receptor-positive breast cancer does not protect fertility.