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Health condition

Adolescent menstrual dysfunction, absent, irregular, heavy or painful periods in teenagers.

Not every teenage period problem is a passing phase. A structured assessment, honest lifestyle review and stepped treatment ladder catch the causes that matter and settle the rest.

Jump to treatment
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Why trust this guide

  • 01

    Editorial team

    Written by our editorial team from the UK sources listed on each page.

  • 02

    Sourced from guidance

    Checked against NICE, RCOG, RCPCH and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK paediatric and adolescent gynaecology practice, including bleeding-disorder screening and hormonal options.

Key facts

Teenage period problems at a glance.

The essentials, in plain English. What counts as normal in the first years of periods, which patterns need a proper look, and how the common ones are treated in the UK today.

  • What it is

    An umbrella term for menstrual problems in teenagers: absent, infrequent, heavy or painful periods that fall outside expected patterns for age and pubertal stage.

  • Primary amenorrhoea

    No menstruation by age 15, or by 3 years after thelarche (breast bud development). Warrants structured assessment of puberty, weight and pelvic anatomy.

  • Secondary amenorrhoea

    Three or more missed cycles in someone with previously established periods. Pregnancy, weight change, exercise load and stress are common drivers.

  • Oligomenorrhoea

    Cycles longer than 45 days in the first post-menarchal year, or longer than 35 days after year two. Very common early on and often self-limiting.

  • Heavy menstrual bleeding

    Anovulatory cycles are the usual cause in the first 2 to 3 years, but a bleeding disorder such as von Willebrand disease should always be considered.

  • Dysmenorrhoea

    Primary period pain is prostaglandin-mediated and typically responds to NSAIDs. Pain that emerges later or worsens over time may signal endometriosis.

Why this guide matters

A structured plan, not a shrug.

Adolescent periods are often dismissed as something to grow out of. Most patterns do settle, but some point to conditions that respond much better to early treatment.

  • Age and pubertal stage matter

    What is normal at 12 is different at 16. Assessment always starts with age at thelarche and menarche, growth pattern and Tanner staging.

  • Bleeding disorders are missed

    Very heavy periods from the very first cycle are still frequently attributed to hormones. A von Willebrand screen changes management.

  • Pain is not something to endure

    Period pain that keeps a teenager out of school is not normal. NSAIDs, lifestyle measures and, when needed, hormonal treatment work.

How the assessment is made

From cycle diary to a clear plan.

The steps a UK GP or paediatric gynaecologist will normally follow, in order, so you know what to expect and why.

  1. 01

    Assessing

    Menstrual and pubertal history

    Age at thelarche and menarche, cycle pattern, bleeding volume, pain, sexual activity and family history of menarche and bleeding disorders.

  2. 02

    Assessing

    Tanner staging and growth

    A structured pubertal exam alongside height, weight and BMI trajectory helps distinguish delayed puberty from constitutional variation.

  3. 03

    Assessing

    Lifestyle and wellbeing screen

    Sport load, energy availability, eating patterns, sleep and stress. Screen sensitively for eating disorders and school pressure.

  4. 04

    Confirming

    Focused blood tests

    TSH and prolactin in most cases; FSH, LH and oestradiol if amenorrhoea; androgens if hyperandrogenic features; coagulation and von Willebrand screen if heavy bleeding.

  5. 05

    Confirming

    Pregnancy test if relevant

    Always considered in secondary amenorrhoea when the young person is or may be sexually active, handled with privacy and sensitivity.

  6. 06

    Confirming

    Pelvic ultrasound

    Transabdominal ultrasound is preferred under 16 and used selectively to assess uterine and ovarian anatomy; transvaginal only if age-appropriate and consented.

  7. 07

    Referral

    Paediatric gynaecology referral

    For suspected outflow obstruction, primary amenorrhoea with abnormal exam, persistent heavy bleeding, or symptoms not settling on first-line treatment.

Typical timeline: a first visit to a settled plan within a few weeks.

Symptoms

What adolescent menstrual dysfunction looks like.

Absent, infrequent, heavy or painful periods, sometimes with clues that point to an underlying hormonal, bleeding or gynaecological cause.

  • No periods by age 15

    Primary amenorrhoea, or no periods 3 years after breast development, needs a structured pubertal and pelvic assessment.

  • Missed periods after regular cycles

    Three or more missed cycles once periods are established. Consider pregnancy, weight change, exercise load, stress and thyroid or prolactin causes.

  • Infrequent cycles

    Oligomenorrhoea, with cycles longer than 45 days early on or 35 days later, is often anovulatory and may point to PCOS.

  • Heavy menstrual bleeding

    Flooding, clots, changing protection hourly, or bleeding beyond 7 days. Anaemia symptoms and school absence matter.

  • Period pain that limits life

    Pain missing school, sport or sleep is not normal. Primary dysmenorrhoea usually responds to NSAIDs; secondary causes need review.

  • Hyperandrogenic signs

    Acne, hirsutism, weight gain or irregular cycles together raise PCOS as a working diagnosis.

  • Low energy availability

    High training load with restricted intake can suppress menstruation. Long-term impact on bone health matters.

  • Red flag - heavy bleeding from menarche

    Very heavy periods from the first cycle, or a family history of bleeding, needs a von Willebrand and coagulation screen.

Treatment

How adolescent menstrual problems are treated.

Reassurance and lifestyle first, then NSAIDs and tranexamic acid, hormonal options for cycle control and bleeding, and treatment of any underlying cause.

  • Reassurance and observation

    Irregular cycles in the first 2 to 3 years after menarche are usually anovulatory and self-limiting. Cycle tracking with a diary or app is enough for many.

  • Lifestyle support

    Address weight, energy availability, training load, sleep and stress. Involve a dietitian or eating disorder service where relevant.

  • NSAIDs

    Mefenamic acid or ibuprofen taken with food from the first sign of bleeding reduces both period pain and heavy menstrual bleeding.

  • Tranexamic acid

    A non-hormonal option for heavy menstrual bleeding, taken during the days of bleeding. Useful when hormonal treatment is not wanted.

  • Combined oral contraceptive

    Regulates cycles, reduces bleeding and pain, and helps hyperandrogenic acne. Blood pressure, migraine history and thrombosis risk are checked first.

  • Progestogen-only options

    The progestogen-only pill or cyclical progestogen can regulate cycles and reduce bleeding when oestrogen is unsuitable.

  • LNG-IUS (Mirena)

    Highly effective for heavy menstrual bleeding in older adolescents. Insertion is planned carefully, sometimes under general anaesthetic.

  • Treat the underlying cause

    PCOS, thyroid disease, hyperprolactinaemia, eating disorders and inherited bleeding disorders each need their own targeted plan.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP or paediatric gynaecologist knows your child and their history, and can tell you which parts apply to them. If in doubt, get seen.

  • NICE. Heavy menstrual bleeding: assessment and management (NG88).

  • RCOG. Green-top and patient information guidance on adolescent menstrual problems.

  • RCPCH. Adolescent health and puberty resources.

  • British Society for Paediatric and Adolescent Gynaecology (BritSPAG). Standards for adolescent gynaecology.

Red flags

When adolescent periods need urgent attention.

Most cases are manageable in primary care with a stepped approach. These are the situations that are not, and where paediatric gynaecology or another specialist input is needed.

  • Primary amenorrhoea with abnormal exam

    No periods by 15 with absent breast development, or with virilisation, cyclical pain and a pelvic mass, needs urgent paediatric gynaecology review.

  • Cyclical pain without menstruation

    Monthly pain with no bleeding may indicate outflow obstruction such as an imperforate hymen or transverse vaginal septum. Refer urgently.

  • Very heavy bleeding from menarche

    Flooding, hospital attendance or transfusion needs from the first period suggests a bleeding disorder. Screen for von Willebrand disease and coagulopathy.

  • Signs of anaemia

    Fatigue, breathlessness, dizziness or pallor with heavy bleeding warrants full blood count, ferritin and prompt treatment.

  • Suspected eating disorder

    Amenorrhoea with low weight, rapid weight loss, restrictive eating or over-exercise needs specialist CAMHS or eating disorder input.

  • Galactorrhoea or visual symptoms

    Milk discharge, headaches or visual field changes with amenorrhoea point to a prolactin-secreting pituitary lesion.

  • Rapid virilisation

    Deepening voice, clitoromegaly or rapid hirsutism needs urgent endocrine assessment to rule out androgen-secreting tumours.

  • Suspected pregnancy

    Any secondary amenorrhoea in a young person who is or may be sexually active needs a sensitive pregnancy test and safeguarding-aware care.

  • Pain and pelvic mass

    A palpable mass with menstrual disturbance requires imaging and paediatric gynaecology review to rule out ovarian pathology.

Living with it

A treatable pattern, with a clear ladder.

Four things that make the biggest difference day to day. A cycle diary, sensible fuelling, early pain relief and a willingness to ask for review when life is affected.

A quiet reminder

Consistency beats intensity, every time.

Small, steady habits, kept up for months, do more than a heroic week that does not last.

  1. 01 Track

    Keep a simple cycle diary

    A short note of start date, days of bleeding, heaviness and pain over 3 to 6 months tells the clinician far more than memory alone.

  2. 02 Balance

    Fuel the body properly

    Adequate energy intake supports regular cycles, growth and bone health, especially with heavy sport or dance schedules.

  3. 03 Comfort

    Manage pain early

    NSAIDs work best started at the first twinge, not once pain is severe. Heat, hydration and rest still matter.

  4. 04 Escalate

    Ask for review if life is affected

    Missing school, sport or sleep is a reason to seek help. Adolescent menstrual problems are treatable and deserve proper attention.

Frequently asked

Everything we get asked about teenage period problems.

Quick answers on when to worry, what tests are done and which treatments are safe in adolescents.

  • When should we worry about my teenager not having periods?

    If there are no periods by age 15, or 3 years after breast development began, it is worth a structured review. Sooner if there are other concerns such as short stature, cyclical pain without bleeding, or signs of an eating disorder.

  • Are irregular periods in the first year normal?

    Yes. Cycles in the first 2 to 3 years after menarche are commonly anovulatory and irregular. A cycle diary helps, and most settle into a more regular pattern with time. Persistent very long gaps or very heavy bleeding still deserve review.

  • How do we tell if heavy periods are due to a bleeding disorder?

    Very heavy bleeding from the very first period, easy bruising, frequent nosebleeds, or a family history of bleeding problems should prompt a coagulation screen and von Willebrand testing alongside the usual gynaecological work-up.

  • Is period pain that stops school attendance normal?

    No. Primary period pain is common but usually manageable with NSAIDs and lifestyle measures. Pain that regularly stops school, sport or sleep, or that started after years of pain-free cycles, needs review and may point to endometriosis.

  • Is it safe for a teenager to start the pill for periods?

    For many adolescents the combined oral contraceptive or a progestogen-only option is a safe and effective way to regulate cycles, reduce heavy bleeding and treat pain. A clinician will check blood pressure, migraine history, thrombosis risk and personal preference first.

  • When would you refer to a paediatric gynaecologist?

    When there is primary amenorrhoea with an abnormal exam, suspected outflow obstruction, persistent heavy or painful bleeding despite first-line treatment, suspected endometriosis, or when specialist devices such as a Mirena are being considered.

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