Breast Cancer After a Baby

Breast cancer is a common concern among women of reproductive age. To evaluate the

effects of recent childbirth on risk for developing breast cancer before age 55, international researchers pooled individual-level data from 15 prospective cohort studies.

During 9.6 million person-years of follow-up, 18,826 incident breast cancers were diagnosed. Compared with nulliparous women younger than 55, parous women were more likely to be diagnosed with breast cancer up to 24 years after giving birth, particularly if they had family histories of breast cancer, were older at first birth, or gave birth multiple times. Although breast-feeding reduces women's lifetime risk for breast cancer, this practice was not found to modify risk for breast cancer diag…