The aetiological impact of a woman's reproductive history on breast cancer is well established, whereas the prognostic influence of the reproductive pattern is less well described. A literature search with focus on three Danish studies is described. Status as parous/nulliparous and number of births appear to have no prognostic influence. Women who have their first child at an early age have a lower survival than women who have postponed their first childbirth. This may eventually be explained by selection, i.e. that women with an early first full-term pregnancy represent a group with a more malignant disease. Women diagnosed in the first two years after childbirth have a significantly lower survival, probably because the cancer, being subclinical during pregnancy, is affected by the high oestrogen concentrations with aggressive growth as the outcome. Pregnancy after treatment of breast cancer does not appear to have a negative influence on the prognosis.