A female’s first menstrual period, known as menarche, occurs during puberty. Menstruation indicates that the body is mature enough for reproduction. About 98% of girls begin their periods by age 15.
There is unexpectedly large variation in height growth in girls after their first period. Every second girl grows either more or less in length than the 6-8 centimeters that is considered standard.
Some results have been hidden because they may be inaccessible to you
Show inaccessible results