We examined the records of women with primary breast cancer for a history of pregnancy and live births. The patients were all histopathologic T1, 2, N0, M0 white females, untreated post modified radical mastectomy. Patients with a history of interrupted pregnancies have a significantly shorter time to recurrence than those with normal pregnancy history. A trend toward a lower incidence of highly differentiated histological pattern is also observed in cancers from these patients.