Half of all girls within the United States experience their first period before their 13th birthday. However, it’s not terribly unusual to find a girl who began menstruating when she was as young as 9 or as old as 17.
In order to put the age issue into perspective, the following statistics may be helpful: 10% of girls menstruate by the time they’re 11 years old; 90% of girls menstruate by the time they turn 14; and 98% of 15-year-old girls menstruate. If your daughter falls outside this age range, she should be examined by a pediatrician, just to make sure she doesn’t have a medical problem.
Research has shown that African-American girls typically menstruate at the earliest age, followed by Hispanic girls and then non-Hispanic White girls. (Interestingly, there aren’t any particularly reliable statistics for other ethnic groups.) Your doctor will take these facts into consideration when evaluating your daughter’s health.
