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Menstrual Disorders in Teens: Causes, Diagnosis & Treatment

By: Kerry Gannon-Loew, MD, MS, FAAP

For many teens, getting their first period is a big milestone. Menstruation usually starts between ages 10 and 15 years old. It's normal for menstrual cycles to be irregular during the first few years. But sometimes, period problems go beyond the usual ups and downs.

Painful cramps, missed or irregular periods or heavy bleeding can be signs of a menstrual disorder. These issues, while common and treatable, can affect your teen's health, confidence and daily life. It helps to know what's typical, and when to reach out to their doctor.

Below are some of the most common menstrual disorders in teens. Learn what causes them, how they're diagnosed and treatment options.

Amenorrhea (no periods)

Amenorrhea is the absence of menstrual periods.

Types of amenorrhea

  • Primary amenorrhea is when a teen does not get their period by age 15.

  • Secondary amenorrhea is when a teen who was getting regular menstrual periods does not get their period for 3 months in a row or more.

What is a regular menstrual cycle & when does it typically start?

A regular menstrual cycle means having a period about once a month. It is common for teens to have irregular periods in the first 2 to 3 years after their first period.

What causes amenorrhea?

Primary amenorrhea can happen for several reasons, such as:

  • Genetic conditions that affect development

  • Hormone imbalances in the brain

  • Problems with how the uterus, vagina or hymen formed before birth

Both primary and secondary amenorrhea can be related tod:

How is amenorrhea diagnosed?

If your teen hasn't had their first period (menarche) by age 15, or stops having periods for more than 3 months, they should see their doctor for medical evaluation.

A medical provider will:

  • Take a thorough medical history, review weight and vital signs

  • Perform a focused physical exam based on the history and symptoms

  • Order blood work or imaging tests to help determine the cause of amenorrhea including:

    • Pregnancy test

    • Thyroid function tests

    • Hormone levels (FSH, LH, estradiol, prolactin, testosterone)

    • Pelvic ultrasound

    • Blood work to check for other medical conditions, including complete blood count (CBC), inflammatory markers and kidney function tests

How is amenorrhea treated?

Treatment will depend on the underlying cause of amenorrhea. Your child's doctor will recommend the best plan.

Abnormal uterine bleeding (AUB)

Abnormal uterine bleeding (AUB) involves unpredictable timing of periods and variable amount of blood flow. This can include:

  • Bleeding more frequently than every 21 days (counting from the first day of one period to the first day of the next) or less frequently than every 45 days.

  • Flow that is especially heavy or light.

What causes AUB?

One common cause is anovulation, when the ovaries don't release an egg. This is common during the first few years after a teen starts their period. Cycles of hormones are still maturing, and this can lead to irregular or less frequent periods.

It is rare for teens to go more than 3 months between periods, even in the first 2 years. If this happens, a teen should see a medical provider to discuss their periods.

How is AUB diagnosed?

A medical provider will:

  • Take a thorough medical history

  • Do a focused physical exam. A pelvic exam is usually not needed or recommended to diagnosis AUB.

  • Order tests, if needed to help rule out other causes and make sure bleeding is not too heavy. These may include:

    • Pregnancy test

    • Testing for sexually transmitted infections (STIs)

    • Blood count to check for anemia

    • Thyroid function tests

    • Measure of hormone levels may be helpful depending on the history

How is AUB treated?

Depending on the underlying cause, oral contraceptives (birth control pills) can help regulate period cycles and manage heavy bleeding.

If irregular periods are likely related to anovulation, the teen's medical provider may also provide reassurance and recommend close monitoring of cycles.

Dysmenorrhea (painful periods)

Within a year or two of their first period, 50-75% of teens begin to experience painful menstrual cramps, called dysmenorrhea.

For most teens, cramps happen because of chemicals called prostaglandins, which are released by the uterus and cause pain. Treatments can help manage symptoms.

Some cases of dysmenorrhea may be related to a gynecologic disorder called endometriosis. With endometriosis, tissue that normally lines the inside of the uterus grows outside of it, in other areas of the pelvic cavity (lowest part of the abdomen). This causes pain.

Symptoms of dysmenorrhea

Symptoms typically begin 1 to 2 days before the start of bleeding and include:

  • Severe cramping

  • Occasional sharp pains in the lower abdomen, lower back and thighs

  • Sweating

  • Fatigue

  • Headache

  • Dizziness

  • Nausea and vomiting

  • Diarrhea

How dysmenorrhea is diagnosed

A health care provider will:

  • Take a thorough medical and family health history, as well as menstrual history.

  • Do a focused physical exam. Usually, a pelvic exam is not needed. Blood work and imaging typically are not needed to diagnosis dysmenorrhea, either.

  • If a provider suspects endometriosis (for instance, if there is a strong family history and cramps do not respond to treatment), they may recommend further evaluation or referral to a specialist.

How is dysmenorrhea treated

  • NSAIDs (nonsteroidal anti-inflammatory drugs such as ibuprofen or naproxen). These medications block the uterus from releasing prostaglandins (the chemicals causing the pain).

  • Acetaminophen may be helpful if a teen cannot take ibuprofen.

  • Certain contraceptives can also be used to relieve cramps. These methods include combined hormonal contraceptives, oral progestins and the progestin injection (Depo Provera), as well as the contraceptive implant (Nexplanon) and levonorgestrel intrauterine device (IUD).

Heavy menstrual bleeding

When is menstrual bleeding considered heavy?

  • Bleeding lasts more than 7 days

  • Bleeding soaks through 1 or more pads or tampons in 1-2 hours, for multiple hours

  • Needing to wear double protection (more than one pad or a pad and a tampon at one time) to control bleeding

  • Needing to change pads or tampons during the night

  • Passing blood clots that are quarter-size or larger

What causes heavy menstrual bleeding?

Heavy periods in teens often happen because they aren't ovulating regularly. When ovulation doesn't occur, the lining of the uterus can build up and lead to heavier bleeding during a period. Other possible causes:

How is heavy menstrual bleeding evaluated?

If a teen is experiencing heavy periods, it is recommended they see a medical provider to discuss the symptoms.

The provider will:

  • Take a thorough history, including family history

  • May recommend labs to evaluate for anemia (blood counts and iron level) and hormones to check for other causes

How is heavy menstrual bleeding treated?

  • Oral contraceptives often make periods lighter and shorter. Levonorgestrel IUDs can significantly lessen bleeding or cause periods to stop.

  • Tranexamic acid: prescription medication to treat heavy menstrual bleeding

When should your teen see a health care provider about period concerns?

  • Not having a period by age 15, going greater than 3 months between periods or periods still irregular after 2 years.

  • Heavy periods that require changing a menstrual product every 1-2 hours or lasting longer than 7 days.

  • A change in periods. If periods were previously happening every month and are now irregular.

  • Significant cramps or other symptoms at the time of periods that are limiting daily activities or leading to missed school.

Remember

If your teen’s periods seem unusual, cause significant discomfort or interfere with their everyday activities, reach out to their doctor. Early evaluation and care can help your teen feel better and stay healthy.

More information

About Dr. Gannon-Loew

Kerry Gannon-Loew, MD, MS, FAAP, is a board-certified pediatrician and adolescent medicine physician and an Assistant Professor of Pediatrics at the University of Wisconsin School of Medicine and Public Health. She is a member of the American Academy of Pediatrics Section on Adolescent Health and has a special interest in working with adolescents with eating disorders, menstrual concerns and substance use disorders.


Last Updated
12/19/2025
Source
American Academy of Pediatrics (Copyright © 2025)
The information contained on this Web site should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances.
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