What’s a normal menstrual cycle for my teenager daughter?

Teenage periods and cycle natural womanhood

By definition, the teen years are a time of transition from childhood to adulthood. With transitions comes change, which often leads to questions, concerns and confusion. Parents of teenage girls are often not sure what’s considered normal (healthy) when it comes to the hormone-driven reproductive development of their daughters and their menstrual cycle. With that in mind, the American College of OB/GYNs (ACOG) has issued a Committee Opinion paper called, “Menstruation in Girls and Adolescents: Using the Menstrual Cycle as a Vital Sign.”

Yes. A VITAL sign. Like your blood pressure or heart rate. The female cycle ought to be used as an indicator of health. Yes, great. So let’s outline what’s considered healthy for young women aged 12-18, according to ACOG.

By the numbers

Menarche is clinician-speak for first period. It’s interesting to note that despite industrialization of our environment and changes to our lifestyle, the median (midpoint) age of menarche in American girls has remained relatively stable for the past 30 years. Most girls get their first bleed around 12 to 13 years old.

From that point on we have a few more interesting stats on this teenage vital sign:

Average time between bleeds (menstrual cycle interval):     32.2 days in the first gynecologic year

Normal range for menstrual cycle interval:                      21-45 days

Menstrual flow length:                                                  7 day OR LESS

Product use:                                                                 3 to 6 pads or tampons per day

When to see an OB/GYN

In the interest of early detection of menstrual patterns that might lead to health concerns later on, ACOG encourages parents to bring their daughter in for an exam if her periods have not started:

  • Within 3 years of breast development
  • By 14 years of age with sign of hirsutism
  • By 14, with a history or physical exam suggestive of excessive exercise or eating disorder
  • By age 15

Once your daughter has started menstruating, ask her to get into the habit of tracking her bleeding (pen/paper works fine, or an app ). Then, let her know that she needs to tell you if she has periods that:

  • Occur more frequently than every 21 days or less frequently than every 45 days
  • Even once, don’t appear for as long as 90 days
  • Last more than 7 days
  • Require frequent product changing (soaking more than one product every 1-2 hours)

Soaking more than one product every 1-2 hours is defined as heavy bleeding and should be evaluated by an OB/GYN, especially if there’s a history of excessive bruising or bleeding in the young lady or her family.

Menstruation is a normal, healthy part of development for young women and they should be taught WHY it is considered normal and healthy. ACOG’s opinion paper states: “It is preferred that caretakers and clinicians participate in this educational process.”

How and what is your daughter learning about her cycles?

Resources for teen fertility awareness education

Mother Daughter program

The Couple to Couple League realizes that mothers are in a special position to engage their daughters about the gift of their fertility.  Their Mother / Daughter program lets you choose the resources you feel would be the best to communicate with your daughter about fertility awareness.


Teen STAR is a developmental curriculum founded by Hanna Klaus, MD (Sr. Miriam Paul , MMS) that helps adolescents  and young adults to come to terms with their emerging sexuality and fertility and assist them in making responsible decisions.

Guiding Star Cycle Show

The Cycle Show is an educational, interactive, multi-media, fertility awareness workshop for young girls.


The FEMM App helps girls understand their reproductive health in all its physical and emotional complexity.


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