Health Library
The Health Library is a collection of health and wellness resources created for learning and accessibility. Select a topic below for related health information or search for a topic in the search bar for more information on other medical conditions.
Menarche
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Your first menstrual period is called menarche (say "MEN-ar-kee"). It usually starts sometime between ages 11 and 14. But it can happen as early as age 9 or as late as 15. If you are a teenage girl, see your doctor if you have not started having periods by age 15. Menarche is a sign you are growing up and becoming a...
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Puberty begins with hormonal shifts that trigger the development of male and female sex characteristics. In general, puberty usually starts for girls between the ages of 9 and 11, and for most boys between the ages of 9½ and 13 years. The exact age at which puberty starts varies widely among individuals. Having an...
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The menstrual cycle is the series of changes a woman's body goes through to prepare for a possible pregnancy. Most girls start having periods between the ages of 11 and 15. A girl who has not had her first period by age 15 has what is called primary amenorrhea. This is different from infrequent or light menstrual...