Period Pain (Dysmenorrhoea)
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Period Pain (Dysmenorrhoea)
Period pain — symptoms, causes, diagnosis and treatment.
Key fact: Period pain (dysmenorrhoea) affects up to 80% of women at some point in their lives. Around 1 in 10 find it severely disabling. It is the most common cause of short-term work and school absence in women of reproductive age — and in most cases, it is highly treatable with the right medication taken at the right time.
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Treat Period Pain Online →What Is Period Pain (Dysmenorrhoea)?
Period pain — the medical term is dysmenorrhoea (pronounced dis-men-or-EE-a) — refers to painful cramping in the lower abdomen, pelvis, or lower back that occurs before or during menstruation. It is the most common gynaecological complaint worldwide and one of the most common causes of short-term work and school absenteeism in women of reproductive age.
Period pain is not simply normal discomfort to be endured. Up to 10% of women experience dysmenorrhoea severe enough to significantly disrupt daily activities. For many of these women, effective treatment is either not being used at all or is being taken at the wrong dose or too late. Matching the right treatment to the right diagnosis — and taking it at the right time — transforms outcomes for most women.
How Prostaglandins Cause Period Pain
Period pain is driven by prostaglandins — inflammatory signalling molecules produced by the uterine lining (endometrium) in response to falling progesterone at the end of the menstrual cycle. Prostaglandins trigger intense uterine contractions and cause vasoconstriction, reducing blood flow to the uterine muscle and producing ischaemic cramping pain.
Prostaglandin levels are highest in the first 24–48 hours of menstruation — which is why period pain is typically worst on day one or two. This mechanism has a critical treatment implication.
The most important rule in period pain treatment: NSAIDs work by inhibiting the COX enzymes that produce prostaglandins. They are most effective when taken at the very first sign of pain or bleeding — before prostaglandin levels peak. Waiting until pain is severe means fighting an already-established inflammatory process.
Primary vs Secondary Dysmenorrhoea
| Type | Definition | Age of onset | Key features | Response to NSAIDs |
|---|---|---|---|---|
| Primary dysmenorrhoea | Pain with no identifiable underlying cause; prostaglandins only | Adolescence — soon after periods begin | Cramping limited to period days; pelvic exam normal | Usually good with correct timing and dose |
| Secondary dysmenorrhoea | Pain caused or worsened by an underlying gynaecological condition | Usually later (20s–40s); or any age with new worsening | May begin before the period; often accompanied by heavy bleeding, dyspareunia or other symptoms | Often partial — treating the underlying condition is essential |
Symptoms and Severity
Dysmenorrhoea pain is characteristically:
- Cramping, throbbing, or spasming in the lower abdomen
- Radiating to the lower back and inner thighs
- Starting just before or at the onset of bleeding
- Worst in the first one to two days of menstruation
- Accompanied by nausea, headache, diarrhoea, or light-headedness in more severe cases
Pain that may indicate secondary dysmenorrhoea: Pain that worsens progressively over years, starts before the period, persists after it, is accompanied by pain during sex, or does not respond to prescription NSAIDs should prompt GP assessment to rule out endometriosis, adenomyosis, fibroids, or pelvic inflammatory disease.
NICE-Recommended Treatment Approach
| Treatment | Mechanism | When to use | NICE position |
|---|---|---|---|
| NSAID (naproxen, ibuprofen) | Inhibits COX enzymes → reduces prostaglandin synthesis | At first sign of pain; during painful days | First-line pharmacological treatment |
| Paracetamol | Central analgesia; does not reduce prostaglandins | Alongside NSAIDs for additive relief | Less effective alone; useful in combination |
| Combined oral contraceptive pill | Suppresses ovulation → reduces endometrial proliferation and prostaglandin production | Women who also want contraception; ongoing prevention | Effective for primary dysmenorrhoea |
| Levonorgestrel IUS (Mirena) | Local progestogen → thins endometrium; dramatically reduces prostaglandin production | Women wanting long-term relief; heavy periods concurrently | Highly effective; NICE recommended for heavy and painful periods |
| Heat therapy | Local vasodilation; reduces muscle spasm | Alongside NSAIDs for mild–moderate pain | Moderate evidence; comparable to low-dose ibuprofen in mild dysmenorrhoea |
| TENS | Electrical nerve stimulation; modulates pain signals | Non-pharmacological add-on | Reasonable evidence for high-frequency TENS |
NSAIDs: Naproxen, Ibuprofen and Mefenamic Acid
| NSAID | OTC dose | Prescription dose | Duration | Key advantage |
|---|---|---|---|---|
| Naproxen | 250mg as first dose, then 250mg every 6–8h | 500mg twice daily | 8–12 hours | Twice-daily dosing; sustained all-day relief; most convenient |
| Ibuprofen | 400mg every 6–8h | 600mg three times daily | 4–6 hours | Fastest onset; most widely available; flexible dosing |
| Mefenamic acid | Not available OTC | 500mg three times daily | 6–8 hours | Also reduces heavy bleeding; dual prostaglandin action; prescription only |
All three should be taken with food to reduce gastrointestinal side effects. NSAIDs are contraindicated in peptic ulcer disease, significant kidney impairment, and aspirin-sensitive asthma. Always start at the first sign of period pain — do not wait until pain is severe.
Prescription-Strength Options
Over-the-counter doses of ibuprofen (400mg) and naproxen (250mg) are starting doses. For women with moderate-to-severe dysmenorrhoea, prescription-strength doses provide meaningfully better relief:
- Naproxen 500mg twice daily — morning and evening during the painful days; sustained all-day prostaglandin suppression; fewer doses needed than ibuprofen
- Ibuprofen 600mg three times daily — faster onset; higher peak anti-inflammatory concentration; take with food or milk
- Mefenamic acid 500mg three times daily — particularly useful when period pain accompanies heavy bleeding; prescription only
Get Prescription Period Pain Relief Online
Access Doctor’s GPhC-registered pharmacist independent prescribers can assess your suitability for prescription naproxen or ibuprofen 600mg via a short online consultation. No GP appointment needed.
Start Consultation →Naproxen 500mg
Twice-daily dosing for all-day relief. First-line prescription NSAID for dysmenorrhoea.
View product →Ibuprofen 600mg
Prescription-strength ibuprofen. Fast onset; three times daily during painful days.
View product →Heat, TENS and Non-Pharmacological Options
Non-pharmacological approaches are most effective as additions to NSAIDs, not substitutes for them in moderate-to-severe dysmenorrhoea.
- Heat pad or hot water bottle — applied to the lower abdomen; local vasodilation and muscle relaxation. Evidence shows heat to be comparable to low-dose ibuprofen in mild pain; significantly enhances NSAID effect when combined.
- High-frequency TENS — transcutaneous electrical nerve stimulation at the lower abdomen; reasonable RCT evidence for reducing dysmenorrhoea severity. Portable devices are available OTC. Useful for women who cannot take NSAIDs.
- Exercise — low-intensity movement and yoga have modest evidence for reducing dysmenorrhoea, likely via improved pelvic blood flow and endorphin release.
- Omega-3 supplementation — may reduce prostaglandin production; limited evidence but safe as an adjunct.
Related Conditions: When Period Pain Signals Something More
Severe, progressive, or treatment-resistant period pain may be secondary to an underlying gynaecological condition. These conditions require specialist investigation and targeted treatment beyond standard NSAIDs.
Endometriosis
Tissue similar to the uterine lining grows outside the uterus — on ovaries, fallopian tubes, bladder or bowel. Causes severe, progressive dysmenorrhoea, deep dyspareunia and chronic pelvic pain. Affects 1 in 10 women. Average UK diagnosis delay: 8 years. Requires laparoscopic confirmation.
Adenomyosis
Uterine lining tissue grows into the muscular wall of the uterus. Causes heavy, prolonged and severely painful periods and a bulky, tender uterus. Predominantly affects women aged 30–50. Frequently underdiagnosed. Hormonal treatments (Mirena IUS, combined pill) are highly effective.
Uterine Fibroids
Non-cancerous muscular growths in or around the uterus that can worsen period pain and cause heavy bleeding. Common — present in up to 70% of women by age 50, though most cause no symptoms. Submucosal fibroids are most likely to cause dysmenorrhoea.
PCOS
Disrupts ovulation, leading to irregular cycles and sometimes severe cramping when periods do occur — often after a longer break, with a thicker uterine lining. The hormonal imbalance can amplify prostaglandin responses and cause heavy, painful periods.
Pelvic Inflammatory Disease
Infection of the upper reproductive tract often caused by STIs (chlamydia, gonorrhoea). Causes pelvic pain that worsens around periods, alongside fever and abnormal discharge. Prompt antibiotic treatment is essential to prevent tubal damage and preserve fertility.
Ovarian Cysts
Fluid-filled sacs on or in the ovary. Many are functional and resolve spontaneously. Larger cysts or endometriomas can cause pelvic pain that worsens during periods. A ruptured cyst causes sudden severe pelvic pain requiring urgent assessment.
When to Seek Medical Help
Seek emergency care (999 / A&E) for: sudden severe pelvic pain, pelvic pain with fever and vomiting, or acute pain with suspected ruptured ectopic pregnancy or ruptured ovarian cyst.
See your GP or use Access Doctor for:
- Period pain not adequately controlled by prescription-strength NSAIDs
- Pain that is getting progressively worse over months or years
- Pain that begins before the period or persists after it
- Period pain accompanied by pain during sex (deep dyspareunia)
- Period pain with heavy bleeding, or bladder or bowel symptoms
- Difficulty conceiving alongside painful periods
- New or worsening period pain in women over 30 — higher index of suspicion for secondary causes
Period Pain Health Guides
Speak to a UK Prescriber About Period Pain
If period pain is disrupting your life, a short online consultation with our GPhC-registered pharmacist independent prescribers can get you the right prescription treatment quickly — without a GP appointment.
View Period Pain Treatments →Frequently Asked Questions
What causes period pain?
Period pain is caused by prostaglandins — inflammatory molecules produced by the uterine lining as progesterone falls at the end of the cycle. They trigger intense uterine contractions and reduce blood flow to the uterine muscle, causing ischaemic cramping. In primary dysmenorrhoea this is the sole cause. In secondary dysmenorrhoea an underlying condition such as endometriosis, fibroids, or adenomyosis amplifies the process.
What is the most effective treatment for period pain?
NSAIDs — naproxen and ibuprofen — are the most effective evidence-based first-line treatment. They work by reducing prostaglandin synthesis. They must be taken at the first sign of pain or bleeding to be most effective. Prescription doses (naproxen 500mg twice daily; ibuprofen 600mg three times daily) provide meaningfully better relief than OTC doses for moderate-to-severe pain.
What is the difference between primary and secondary dysmenorrhoea?
Primary dysmenorrhoea has no identifiable underlying cause — prostaglandins only, responds well to NSAIDs, typically begins in adolescence. Secondary dysmenorrhoea is caused or worsened by an underlying condition (endometriosis, adenomyosis, fibroids, PID), often starts later in life, may not respond fully to NSAIDs, and requires specialist assessment and treatment.
When should period pain be investigated?
Seek assessment if pain is not controlled by prescription NSAIDs, has worsened progressively over time, extends beyond the period, is accompanied by heavy bleeding or pain during sex, or if you suspect endometriosis or adenomyosis. New or worsening pain in women over 30 always warrants investigation to rule out a secondary cause.
Can endometriosis cause period pain?
Yes — endometriosis is one of the most significant causes of secondary dysmenorrhoea. Tissue similar to the uterine lining grows outside the uterus, bleeding internally each cycle and causing inflammation and adhesions. Pain tends to be severe, progressive, and accompanied by deep dyspareunia. Diagnosis typically requires laparoscopy, and the average diagnosis delay in the UK is 8 years.
Is period pain normal?
Mild to moderate cramping for one to two days is common. But pain that prevents normal activities, requires prescription medication, is getting progressively worse, extends beyond the period, or is accompanied by other symptoms is not something to simply accept — it warrants assessment to rule out an underlying condition.
Can I get prescription period pain relief online?
Yes. Access Doctor’s GPhC-registered pharmacist independent prescribers can assess and prescribe naproxen 500mg and ibuprofen 600mg via a short online consultation. No GP appointment needed. Where clinically appropriate, prescriptions are issued with next-working-day delivery.
What is adenomyosis?
Adenomyosis is where uterine lining tissue grows into the muscular wall of the uterus, causing heavy, prolonged and severely painful periods. It predominantly affects women aged 30–50 and is frequently underdiagnosed. Hormonal treatments including the Mirena IUS and the combined contraceptive pill can significantly reduce symptoms.
References
- National Institute for Health and Care Excellence (NICE). Heavy menstrual bleeding: assessment and management. NG88. 2018 (updated 2023). nice.org.uk/guidance/ng88
- National Institute for Health and Care Excellence (NICE). Endometriosis: diagnosis and management. NG73. 2017 (updated 2024). nice.org.uk/guidance/ng73
- NHS. Period pain (dysmenorrhoea). NHS.uk. nhs.uk/conditions/period-pain
- Marjoribanks J et al. Nonsteroidal anti-inflammatory drugs for dysmenorrhoea. Cochrane Database Syst Rev. 2015. PubMed: 26224322
- Osayande AS, Mehulic S. Diagnosis and initial management of dysmenorrhoea. Am Fam Physician. 2014;89(5):341–346. PubMed: 24695505
Medical disclaimer: This page is for informational purposes only and does not constitute medical advice. Period pain can be a symptom of underlying conditions requiring medical assessment. Always consult a qualified healthcare professional for diagnosis and treatment. In a medical emergency, call 999.
