Starting menstrual periods at a young age is linked to a small increase in breast cancer risk later in life [27,121-123]. Studies have shown a 20 percent (or 1.2-fold) increase in risk among women who began their periods before age 12 compared to those who began their periods after age 14 [122]. This likely relates to the amount of estrogen a woman is exposed to throughout her life. A high lifetime exposure to estrogen is an important risk factor for breast cancer (for more information on estrogen and breast cancer risk, click here). The earlier a woman starts having periods, the longer her breast tissue is exposed to estrogens that are released during the menstrual cycle, and the greater her lifetime exposure to estrogen.
An adult woman cannot change the age at which she started her periods. However, the age a girl starts getting her period can be influenced by a number of factors. For example, girls who are lean and get more physical activity tend to start menstruating at a later age than other girls. It is a good general health recommendation for all young girls to be physically active and not be overweight. It is not recommended that girls do anything to try and influence their age at menstruation.
Updated 08/20/08
