The role of estrogen in women’s breast health is one of balance. While estrogen is required to regulate the functions of the female body, a lifetime exposure to increased estrogen can cause a slight increase in breast cancer risk.
This relationship between lifetime exposure to estrogen and breast cancer risk is not completely understood, but a slightly higher risk of breast cancer in women who start menstruating early and who delay or do not undergo childbirth appears to be related to this concept of a higher lifetime exposure to estrogen in the bloodstream.
Menarche is the age at which a young woman begins her menstrual cycle. The average age of menarche in the US is around 12-13 years. For those who begin to have menstrual periods prior to age 12, there is a slight increase in risk of breast cancer - about 20% higher for those who start before age 12 compared to those women who start after age 14.
As a woman gets older and starts to assess breast cancer risk, age of menarche is another factor to consider - one of those risk factors that cannot be modified. Arming yourself with knowledge, though, can lead to healthy behaviors and regular screenings to help try to deal with the slight increase in risk. Excess estrogen exposure and relation to breast cancer risk is a complex subject which is still under active research. Knowing your breast cancer risk, including those factors like early menarche that cannot be controlled, is an important step in breast self-awareness.
Originally published 2/20/14 on mammographykc.com.