All premenopausal patients should be informed about the potential impact of chemotherapy on fertility and asked about their desire for a possible future pregnancy. Patients who may wish to become pregnant in the future should consult a fertility specialist prior to chemotherapy and/or endocrine therapy to discuss the patient’s options based on specific condition, disease stage, and biology (determine urgency, type, and sequence of treatment). As for the timing and duration of fertility preservation, permissible options include oocyte and embryo cryopreservation and, as technology continues to evolve, discussion of the probability of successful pregnancy after completion of breast cancer treatment. Although amenorrhea often occurs during or after chemotherapy, it appears that most women younger than 35 years of age regain their menstruation within 2 years of finishing adjuvant chemotherapy. There is no necessary link between menstruation and fertility. Irregular menstruation, especially if the patient is taking tamoxifen, does not necessarily imply a lack of fertility. On the contrary, the presence of menstruation does not guarantee fertility. Information on the continuation of fertility after chemotherapy is limited. Patients should not become pregnant during radiotherapy, chemotherapy or endocrine therapy. Despite the limited information, hormonal contraception is frustrating regardless of the hormone receptor profile of the patient’s tumor. Other methods of contraception include intrauterine devices (IUDs), barrier methods of contraception, or tubal ligation or vasectomy of the partner for patients who have no intention of becoming pregnant. Randomized trials have demonstrated that administration of gonadotropin-releasing hormone agonists for ovarian suppression during adjuvant chemotherapy in premenopausal women with ER-negative tumors protects ovarian function and reduces the likelihood of chemotherapy-induced amenorrhea. Breastfeeding is not contraindicated after breast-conserving treatment for breast cancer. However, the quantity and quality of milk produced by the preserved breast may be insufficient or may lack some essential nutrients. Breastfeeding is not recommended during aggressive chemotherapy and endocrine therapy. The small historical experience with gonadotropin-releasing hormone agonist therapy has been reported in patients with ER-positive disease to be significant in its protective effect on fertility.