New research led by an Australian professor has uncovered how having children and breastfeeding reduces a women’s long-term risk of breast cancer.

While it has been known having children can reduce a woman’s breast cancer risk, the reasons were not fully understood and pregnancy-related hormonal changes were thought to be a major factor.

This research, published in the Nature journal today, instead points to immune changes within the breast tissue with mothers who breastfed having more CD8+ T cells — a type of immune cell that can kill tumours — even decades after childbirth.

The study looked at over 1000 patients who were diagnosed with triple-negative breast cancer — the most aggressive form of the disease — after their last child and found those who breastfed had better survival rate

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