A new study shows that moms with breast cancer who previously breastfed have a lower chance of that cancer returning.
You’ve probably heard that breastfeeding lowers your chances of developing breast cancer, but this study examined the relationship a bit further, a fact that the researchers say may make it one of the first of its kind.
A study of over 1,600 women with breast cancer revealed that those who had previously nursed a child had a 30 percent decreased risk of their breast cancer returning. They also discovered that those women had a 28 percent less chance of dying from the disease than their peers who never breastfed.
The study involved two groups of women, some who were diagnosed from 1997 to 2000 and others who were diagnosed from 2006 to 2013. Most were patients at Kaiser Permanente. The study showed a trend toward more positive outcomes for those afflicted with breast cancer, but the study authors do say the research doesn’t prove cause and effect — it only shows a link.
They also found that it didn’t seem to matter how long a mom breastfed her child, but there was less of a link when the duration was six months or less.
It should be noted that the connection was strongest when they studied women who had some of the most common types of breast cancers — those that are known as luminal A subtypes, which includes tumors called estrogen receptor-positive (ER-positive). The statistics weren’t as strongly linked with other subtypes of breast cancers.
Even though it doesn’t show a specific cause and effect, this is encouraging, positive news. Lead author Marilyn Kwan, a research scientist at the Kaiser Permanente division of research, says that breastfeeding causes physical changes that include maturation of cells in the breast that can have a protective effect, making them more resistant to cancer. Breastfeeding also often reduces the number of menstrual cycles a woman experiences over her lifetime, which results in less exposure to hormones.