Reproductive factors can have an important effect on a woman’s risk of developing endometrial cancer by influencing her hormone levels. Changes that increase the level and activity of the female hormone oestrogen can be associated with risk of endometrial cancer.
Reproductive factors associated with an increased risk of endometrial cancer risk include being younger when periods start and being older at menopause.
Some reproductive factors may protect against developing endometrial cancer. This includes having children and breastfeeding.
Age at menopause
Later age at menopause* is associated with an increased risk of endometrial cancer.
The average age of menopause in Australia is 51 years. The risk of endometrial cancer increases by around 6% for every year older a woman is at menopause. For example, a woman who goes through menopause at the age of 55 years has about a 26% higher risk of endometrial cancer than a woman who goes through menopause at age 51 years. Conversely, a woman who goes through menopause at a younger age has a decreased risk of endometrial cancer.
The increased risk of endometrial cancer in women who are older at menopause is likely to be due to hormones. When menopause occurs at a later age, the body is exposed to the female hormone oestrogen for longer. Longer exposure to oestrogen over a woman’s lifetime can increase the risk of endometrial cancer.
The increased risk may also be due to lower levels of the female hormone progesterone in women who are closer to menopause. Progesterone can reduce the effects of oestrogen on endometrial cells. If progesterone levels are lower, the effects of oestrogen are stronger, meaning that the risk of endometrial cancer can increase.
*Menopause occurs when 12 months have passed since a woman’s last menstrual period.
