The effect of subsequent pregnancy on the outcome of a premenopausal woman with a history of breast cancer are suggested to be protective in several series mostly in otherwise healthy mothers with early breast tumors. The literature on the prognostic significance of pregnancy-associated breast cancer (PABC) is far from being consistent. In addition, the topic of subsequent pregnancy in young patients who remain fertile chemotherapy for nonmetastatic disease is of major importance for recovering women who wish to conceive. This chapter focuses on series of at least 50 patients with PABC, which analyzed data after adjusting for known prognostic confounders. It assesses separately the effect of prior and subsequent pregnancies on the prognosis of women with breast cancer. Most data suggest a noninferior outcome in women who subsequently became pregnant, as long as pregnancy was delayed 1-2 years from diagnosis, and possible protective effect if tumors were node-negative.