UNLABELLED: The aim of the present review was to assess the relationship between pregnancy and/or lactation and breast cancer, the influence of pregnancy on mortality and prognosis of the disease, the consequences of breast cancer to the current pregnancy and also to discuss the future perspective for women's fertility.MATERIALS AND METHODS: Articles were obtained from Medline (1988 present) using as keywords breast cancer, pregnancy, breastfeeding, lactation, carcinoma and pregnancy.RESULTS: Unfortunately, delays in diagnosis and treatment are common during pregnancy and the prognosis is thus worsened. Nulliparity, early menarche and late age at first pregnancy are associated with increased risk for breast cancer. Breastfeeding confers a protective effect on risk of breast cancer, which appears to be related to the duration of breastfeeding. In cases of advanced metastatic disease during the first 14 to 15 weeks of pregnancy when chemotherapy is necessary for prompt treatment, termination of pregnancy may be proposed, particularly if the patient is ER-positive. Modified radical mastectomy is probably the procedure most frequently used today. In general chemotherapy should be delayed until after 14 to 15 weeks of gestation and radiation should be reserved until post delivery. Several authorities generally advise that future pregnancy should be delayed for at least two years after breast cancer treatment.CONCLUSION: Breast cancer has an equivalent prognosis in pregnant and non pregnant patients when matched by age and stage at diagnosis. Women are invariably best treated by multidisciplinary teams.