The benefits of breastfeeding just seem to keep growing.  Now, it appears one more benefit can be added and that is a reduced risk of developing endometrial cancer.  This is according to a new study published in Obstetrics and Gynecology, which found women who had ever breastfed their babies were 11 percent less likely than women who had children but didn’t breastfeed to be diagnosed with endometrial cancer.

What appears to matter is the length of time a woman breastfeeds.  Women who breastfed at least six months had lower incidences of endometrial cancer even though there was little extra benefit past breastfeeding more than 9 months.

Endometrial cancer is the fourth most common cancer in women in the United States, Canada, and Australia, according to the International Agency for Research on Cancer.  Endometrial and uterine cancers are becoming more common and any sort of intervention a woman can do to lower her risk is helpful.

The researchers conducted the study by analyzing pooled data from studies participating in the Epidemiology of Endometrial Cancer Consortium, which included 10 from the United States, along with others from Canada, Europe, China and Australia.  Over 26,000 women who had ever breastfed a baby were looked at in addition to how long they did so.  Out of this number of women, about 9,000 of the women had endometrial cancer.

When the researchers took into account factors that influence the development of endometrial cancer such as age, race, education, oral contraceptive use, menopausal status, body mass index and years since last pregnancy, the apparent protective effect of breastfeeding is what remained.

While this study does not prove that breastfeeding will protect against a woman from developing endometrial cancer, there is some merit to it.  Endometrial cancer is stimulated by estrogen which breastfeeding suppresses. To help further assess the findings from this current study, other studies from other countries are required to link the association. 

A recent endometrial cancer report from the World Cancer Research Fund and American Institute for Cancer Research in 2013 classified the evidence for a benefit from breastfeeding as “limited-no conclusion.”

Breastfeeding is also being looked at in other studies as to the effects of it on ovarian cancer.  Women have already been found to have lower incidences of breast cancer if they breastfeed.  The results from this current study add on another possible long-term health benefit women may receive if they breastfeed for at least six months.