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Health condition

Menstrual cramps, explained - and when they signal something more.

Painful periods are common, but they are not something to simply endure. Most respond well to properly timed treatment - and some deserve a closer look.

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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 RCOG, NICE CKS and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK guidance including NSAID timing, the levonorgestrel IUS and when to investigate for secondary causes.

Key facts

Menstrual cramps at a glance.

The essentials, in plain English - what it is, the two types, and how it's treated in the UK today.

  • What it is

    Dysmenorrhoea - crampy suprapubic or lower abdominal pain around menstruation, affecting the majority of menstruating women to some degree.

  • Primary type

    No underlying pelvic pathology - driven by excess prostaglandin production causing uterine contraction and vasoconstriction.

  • Secondary type

    Underlying pathology such as endometriosis, adenomyosis or fibroids - typically develops later and behaves differently.

  • First-line treatment

    NSAIDs - mefenamic acid, ibuprofen or naproxen - most effective when started just before or at the onset of bleeding.

  • Hormonal options

    The combined pill or the levonorgestrel intrauterine system reduce both flow and pain, and offer contraception too.

  • When to worry

    Worsening pain, pain outlasting the period, or deep dyspareunia point towards a secondary cause needing gynaecology review.

Why this guide matters

Knowing the difference changes everything.

Most period pain is primary and manageable. A minority is secondary and needs investigation. The three points below shape everything else on this page.

  • Timing of NSAIDs matters

    Starting mefenamic acid or ibuprofen just before or at the onset of bleeding works far better than waiting for pain to build.

  • Hormonal options do double duty

    The combined pill and the levonorgestrel IUS both reduce pain and provide contraception where it is wanted.

  • Progression is the key clue

    Pain that changes, worsens or outlasts the period is the strongest signal to look for endometriosis, adenomyosis or fibroids.

How the diagnosis is made

From painful periods to a clear plan.

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

  1. 01

    Assessing

    Menstrual and pain history

    Onset relative to menarche, pain pattern, severity and how it has changed over time.

  2. 02

    Assessing

    Screen for secondary features

    Deep dyspareunia, abnormal bleeding or subfertility are red flags that point towards endometriosis or adenomyosis.

  3. 03

    Assessing

    Impact on daily life

    Effect on school, work attendance and quality of life shapes how quickly to escalate treatment.

  4. 04

    Confirming

    Pelvic examination

    Selective - particularly if a secondary cause is suspected or the patient is sexually active.

  5. 05

    Confirming

    Transvaginal ultrasound

    If secondary dysmenorrhoea is suspected, to look for fibroids, adenomyosis or ovarian cysts.

  6. 06

    Preparing

    Trial of standard treatment

    NSAIDs with or without hormonal contraception, reviewed after two to three cycles.

  7. 07

    Preparing

    Gynaecology referral

    For suspected endometriosis not responding to treatment, or when laparoscopy is being considered.

Typical timeline: a first visit to a settled plan within two to three cycles.

Symptoms

What menstrual cramps actually feel like.

The classic pattern of primary dysmenorrhoea - and the features that mean it's worth looking more closely.

  • Crampy suprapubic pain

    Lower abdominal pain that may radiate to the back or thighs - the hallmark symptom of dysmenorrhoea.

  • Timing with bleeding

    Primary dysmenorrhoea starts with or just before bleeding and typically lasts one to three days.

  • Nausea and diarrhoea

    Prostaglandin-mediated gut effects are common alongside the cramping pain.

  • Fatigue and headache

    Tiredness, headache and mood changes often accompany the pain in the days around a period.

  • Pain that is changing or worsening

    A pattern that progresses over time, rather than staying stable, suggests a secondary cause.

  • Deep dyspareunia

    Pain during deep penetration is a key feature suggesting endometriosis or adenomyosis.

  • Later onset in reproductive life

    New or changing pain developing well after adolescence points away from a purely primary cause.

  • Red flag - persisting beyond the period

    Pain that continues after bleeding stops deserves gynaecology assessment for secondary causes.

Treatment

How menstrual cramps are treated in the UK.

NSAIDs first, hormonal options next, and a proper look for secondary causes when standard treatment does not work.

  • NSAIDs

    Mefenamic acid, ibuprofen or naproxen - first-line, most effective when started just before or at the onset of bleeding.

  • Combined oral contraceptive pill

    Reduces menstrual flow and pain, and is particularly useful if contraception is also wanted.

  • Levonorgestrel intrauterine system

    Mirena - effective for pain reduction alongside long-acting contraception.

  • Heat therapy

    Heat pads or a hot water bottle - simple, accessible and supported by evidence.

  • Lifestyle measures

    Regular exercise and stopping smoking, which is associated with worse dysmenorrhoea.

  • TENS

    Transcutaneous electrical nerve stimulation - selective evidence for additional pain relief.

  • Investigating secondary causes

    Transvaginal ultrasound and gynaecology referral when endometriosis, adenomyosis or fibroids are suspected.

  • Laparoscopy referral

    For suspected endometriosis strongly suggested by history and not responding to standard treatment.

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 gynaecologist knows your history and can tell you which parts apply to you. If in doubt, get seen.

  • Royal College of Obstetricians and Gynaecologists (RCOG). Guidance on dysmenorrhoea and endometriosis.

  • NICE Clinical Knowledge Summaries (CKS). Dysmenorrhoea.

  • NICE. Endometriosis: diagnosis and management (NG73).

  • Endometriosis UK. Patient information and support resources.

Red flags

When period pain needs closer attention.

Most period pain is manageable in primary care. These are the situations that aren't - and where a specialist opinion is needed.

  • Pain outlasting the period

    Cramping that persists beyond bleeding is unusual for primary dysmenorrhoea and warrants assessment.

  • Progressive worsening

    Pain that gets worse cycle after cycle, rather than staying stable, suggests a secondary cause such as endometriosis.

  • Deep dyspareunia or subfertility

    Pain with deep penetration or difficulty conceiving alongside painful periods are classic endometriosis features.

  • New onset after the copper IUCD

    A copper coil can worsen cramping - review the device if pain is new or has intensified since fitting.

  • Fever with pelvic pain

    Fever alongside pelvic pain raises the possibility of pelvic inflammatory disease and needs prompt assessment.

  • Sudden severe unilateral pain

    Acute, severe one-sided pain can indicate ovarian torsion or a ruptured cyst - this needs emergency care.

  • Abnormal or heavy bleeding

    Heavy menstrual bleeding alongside cramps can point to fibroids or adenomyosis and deserves a proper work-up.

  • No response to standard treatment

    Failure of NSAIDs and hormonal options after a fair trial is a clear signal to investigate further.

  • Pain starting well after menarche

    Dysmenorrhoea that begins years after periods started, rather than with them, is more likely to be secondary.

Living with it

A manageable condition, with a clear ladder.

Four things that make the biggest difference month to month - timing your painkillers, using heat, tracking your pattern and not normalising severe pain.

A quiet reminder

Painful periods are common - they don't have to be unbearable.

There is a well-tested ladder of treatment. If you are still on the bottom rung after months of trying, it is time to ask for the next step.

  1. 01 Timing

    Start NSAIDs early

    Taking mefenamic acid or ibuprofen just before or at the first sign of bleeding works better than waiting until pain is severe.

  2. 02 Heat

    Use a hot water bottle

    Heat therapy is simple, safe and genuinely evidence-based for easing cramping pain.

  3. 03 Track

    Keep a pain and cycle diary

    Recording pain severity and timing over a few cycles makes it far easier to spot a secondary pattern.

  4. 04 Escalate

    Don’t normalise severe pain

    Pain that stops you going to school or work is not something to just put up with - ask for a proper review.

Frequently asked

Everything we get asked about menstrual cramps.

Quick answers on causes, painkillers, hormonal options and endometriosis.

  • What causes menstrual cramps?

    Most period pain is primary dysmenorrhoea - excess prostaglandin production causes the uterine muscle to contract and blood vessels to narrow, with no underlying pelvic disease. It typically begins with the onset of ovulatory cycles in adolescence and lasts one to three days.

  • How do I know if my period pain is normal or something else?

    Primary dysmenorrhoea starts with or just before bleeding, follows a predictable one-to-three-day pattern, and responds to NSAIDs. Pain that worsens over time, persists after the period ends, or comes with deep dyspareunia or subfertility suggests a secondary cause such as endometriosis, adenomyosis or fibroids.

  • What is the best painkiller for period pain?

    NSAIDs such as mefenamic acid, ibuprofen or naproxen are first-line and work by reducing prostaglandin production. They are most effective when started just before or at the onset of bleeding, rather than once pain is already severe.

  • Can contraception help with period pain?

    Yes. The combined oral contraceptive pill and the levonorgestrel intrauterine system (Mirena) both reduce menstrual flow and pain, and are useful options if contraception is also wanted.

  • When should I see a doctor about period pain?

    See your GP if pain is not controlled by standard NSAIDs and hormonal options, if it worsens over time, if it persists beyond your period, or if you have deep dyspareunia, abnormal bleeding or difficulty conceiving. These features can point towards endometriosis, adenomyosis or fibroids.

  • Could my period pain be endometriosis?

    It is a key differential, especially if pain has developed later in reproductive life, is progressively worsening, or is associated with deep dyspareunia or subfertility. If standard treatment does not help, a gynaecology referral for further assessment, including transvaginal ultrasound and possibly laparoscopy, is appropriate.

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