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Children's Health

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Menstruation: What's Normal for Girls

New Guidelines Call for Routine Checks, List 12 Menstrual Warning Signs in Young Girls
WebMD Health News
Reviewed by Louise Chang, MD

Nov. 7, 2006 -- New guidelines explain what to expect -- and when to see a doctor -- during a girl's first years of menstruation.

The guidelines come from the American Academy of Pediatrics' Committee on Adolescence along with the American College of Obstetricians and Gynecologists' Committee on Adolescent Health.

The committees recommend that doctors view girls' menstruation as a "vital sign" at medical checkups, just like temperature and heart rate.

And as they enter puberty, girls should get preventive checkups to learn about their reproductive health in a confidential setting, the doctors add.

Girls are 12-13 years old, on average, when they get their first menstrual period (menarche), the committees note.

That average age hasn't changed much in 30 years, though black girls go through menarche five months earlier than they did 30 years ago, according to the committees.

Their report appears in the November edition of Pediatrics.

What to Expect

Here are some facts cited in the report about girls' first periods:

  • Typically start two to two-and-a-half years after breast development begins.
  • Generally last two to seven days.
  • Menstrual cycles range from 21 to 45 days.
  • Charting periods can help uncover any menstrual changes or problems.

A menstrual cycle lasts from the first day of a girl's period until the first day of her next period.

During the early years of menstruation, girls usually have "medium" menstrual flow; "most report changing a pad approximately three to six times a day," according to the report.

Girls who go three months without a period after they begin menstruating should get a checkup, say the committees.

The checkups can screen for pregnancy and for problems such as hormonal imbalances and eating disorders.

12 Warning Signs

The doctors list 12 menstrual conditions that may require medical evaluation:

  • No menstrual period within three years of breast development.
  • No menstrual period by age 13, with no signs of pubertal development.
  • No menstrual period by 14, with signs of excess facial or body hair (hirsutism).
  • No menstrual period by 14, with a history or examination suggestive of excessive exercise or an eating disorder.
  • No menstrual period by 14, with concerns about genital tract problems.
  • No menstrual flow by 15.
  • Menstrual periods that become "markedly irregular" after happening regularly every month.
  • Menstrual periods occurring more than every 21 days.
  • Menstrual periods occurring less than every 45 days.
  • Menstrual periods occurring 90 days apart, even for one cycle.
  • Menstrual periods that last more than seven days.
  • Menstrual periods requiring frequent pad/tampon changes (more than once every one or two hours).

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