Menarche is the name given to the time when a girl has her first period. The age at which this happens varies from person to person. Most girls experience the menarche between the ages of 10 and 14 years. This age has been dropping for several years, probably due to improved nutrition and better social conditions.

Before their first period arrives, most girls will have shown the early signs of puberty — the beginnings of breast development and fine hair growth in the pubic region and axilla (armpit). If signs of puberty begin much earlier, before age 8 for girls, it is called precocious puberty. This may be normal for that individual, or it may be a sign of underlying hormonal problems, so it’s best to get children with very early puberty reviewed by their doctor.

It is uncommon for a regular menstrual cycle to follow the first period. Periods tend to occur in a haphazard way for the first year or 2 before settling into a regular pattern, which is usually once every 24 to 30 days.

Some girls experience their first period without knowing what it is, which can be a frightening experience. For this reason it is important for parents to prepare their daughters in advance for the changes associated with growing up.

Last Reviewed: 9 August 2013
Your Doctor. Dr Michael Jones, Medical Editor.


1. The American College of Obstetricians and Gynecologists. Your first period: FAQs (Dec 2012). (accessed Jun 2013).
2. Menstruation: preparing your preteen for her period (updated 4 Aug 2011). (accessed Jun 2013).
3. Precocious puberty (updated 3 Feb 2011). (accessed Jun 2013).
Dr Michael Jones

Dr Michael Jones

Medical Editor, Your Doctor.