Endometrial cancer is a type of cancer which stems from the lining of the uterus (called the endometrium).
It’s the most common type of uterine cancer, and the most common gynaecological cancer diagnosed in Australian women.
Various factors such as genes and lifestyle may be related to the risk of endometrial cancer.
Not Breastfeeding Increases The Risk Of Cancer Of The Uterus
It’s thought to be caused by the continuous stimulation of the hormone oestrogen.
Hence, conditions linked to oestrogen may affect the risk of endometrial cancer.
Breastfeeding is an important human biological function and its importance for the health of mothers and children have been well established.
You can read more in Benefits Of Breastfeeding – What Are They Exactly?.
In addition, breastfeeding may influence the risk of endometrial cancer due to the hormonal changes while breastfeeding.
Not Breastfeeding Increases Endometrial Cancer Risk
A recent meta-analysis (a systematic review which provides the highest quality scientific evidence) analysed 8,981 women with endometrial cancer and 17,241 women in a control group.
Ever breastfeeding was associated with an 11% reduction in risk of endometrial cancer. This equates to not breastfeeding increasing the risk of endometrial cancer by 12%.
A Dose Response Relationship Was Found
A dose response relationship between breastfeeding and endometrial cancer risk reduction was found, with a longer average duration of breastfeeding per child being associated with an even lower risk of endometrial cancer.
When a dose response relationship is found in research, this can make researchers more confident in claiming the results are causal rather than just an association.
Compared to women who don’t breastfeed, breastfeeding between 3-6 months reduced a woman’s risk of endometrial cancer by 7% per child.
Breastfeeding for between 6-9 months reduced a woman’s endometrial cancer risk by 11 % per child.
If a woman breastfed three children, each for 9 months, this equates to a 33% reduced risk of endometrial cancer.
The authors concluded: “Our findings suggest that reducing endometrial cancer risk can be added to the list of maternal benefits associated with breastfeeding. Ongoing promotion, support, and facilitation of this safe and beneficial behavior might therefore contribute to the prevention of this increasingly common cancer.”