11/06/2025
Research shows immune changes after breastfeeding could prevent cancer
Written by: Mie Hermansen
Date: November 1, 2025
"A new study suggests that breastfeeding may leave lasting immune protection in mothers, lowering their risk of breast cancer later in life.
Sleepless nights, early mornings, and endless feeding sessions — breastfeeding can feel like a marathon for new mothers.
But science now shows that those long months may leave behind more than memories and midnight feedings. They might also give lasting protection against one of the most feared diseases.
A hidden immune advantage
Researchers from the Peter MacCallum Cancer Centre in Melbourne have found that breastfeeding doesn’t just benefit the baby — it also appears to strengthen the mother’s immune system in ways that could lower her risk of breast cancer later in life.
Published in the journal Nature, the study reveals that women who have breastfed may retain specialized immune cells in their breast tissue for decades.
These cells seem to act as sentinels, monitoring for abnormal activity that could develop into tumors.
Scientists believe this discovery could transform understanding of how the immune system adapts after pregnancy and why mothers tend to have a lower lifetime risk of certain cancers.
Traces of pregnancy that protect for years
Until now, the protective link between childbirth and reduced breast cancer risk was thought to stem mainly from hormonal changes.
But the new research suggests that the body’s immune response may play a much bigger role than previously realized.
The team analyzed breast tissue samples from both healthy women and breast cancer patients, comparing those who had given birth with those who had not.
They also conducted experiments on mice to confirm the immune mechanisms at work.
Results indicated that women who had breastfed retained more immune memory cells — a possible biological shield developed to protect mothers during the vulnerable postpartum period.
These cells may continue to safeguard tissue long after breastfeeding ends, potentially explaining the lower rates of aggressive cancer types such as triple-negative breast cancer among mothers.
What scientists observed
Researchers noted several consistent patterns across both human and animal samples:
Breastfeeding mothers had a higher concentration of immune-related T cells in breast tissue.
These immune cells remained active for many years after lactation ended.
The cells appeared to detect and respond more quickly to cellular changes that can lead to cancer.
The findings could help guide future prevention and treatment strategies, focusing on how to replicate or enhance this natural immune protection in women who haven’t given birth.
While more studies are needed, experts say the research adds to growing evidence that breastfeeding can have powerful, long-term benefits — not only for the child but also for the mother’s health."
https://welltica.com/research-shows-immune-changes-after-breastfeeding-could-prevent-cancer/
