Dysmenorrhoea

Dysmenorrhoea is painful menstruation, classified as primary (no identifiable underlying pelvic pathology, driven by excess endometrial prostaglandin production causing myometrial contraction and ischemia, typically beginning within 1 to 2 years of menarche once ovulatory cycles are established) or secondary (attributable to an underlying condition, most commonly endometriosis, adenomyosis, or fibroids, typically with onset later in reproductive life or a change in a previously established pain pattern).

Primary dysmenorrhoea: crampy, suprapubic pain beginning shortly before or with the onset of menses, lasting 1 to 3 days, often with associated nausea, fatigue, and low back pain, with a normal pelvic examination.

Secondary dysmenorrhoea: pain that may begin earlier in the cycle, persist beyond menstruation, worsen progressively over time, or be associated with other features (deep dyspareunia, abnormal bleeding, subfertility) pointing toward an underlying cause such as endometriosis (see that entry).

Primarily clinical, based on history and a normal pelvic examination for primary dysmenorrhoea.

Red flags prompting investigation for secondary causes: onset after age 25, pain not responding to standard first-line treatment, abnormal bleeding, deep dyspareunia, or an abnormal pelvic examination finding (fixed retroverted uterus, tenderness, or a palpable mass).

Pelvic ultrasound is the first-line investigation where secondary dysmenorrhoea is suspected; laparoscopy remains the gold standard for diagnosing endometriosis specifically (see that entry).

NSAIDs are first line, working directly on the prostaglandin mediated mechanism: mefenamic acid 500 mg PO tds, or ibuprofen 400 mg PO tds to qds, or naproxen 500 mg PO loading dose then 250 mg PO tds, started at or just before the onset of menses and continued for the first 2 to 3 days, generally more effective than paracetamol given the specific prostaglandin mediated mechanism
Hormonal treatment where NSAIDs are insufficient, contraception is also desired, or as an alternative first-line option: combined oral contraceptive (cyclical or continuous/extended regimens, the latter reducing the frequency of withdrawal bleeds and associated pain), the levonorgestrel-releasing IUD, or the progestogen-only pill/injection
Heat application (heat pads) has modest supporting evidence as a low-risk adjunct
Secondary dysmenorrhoea is managed according to the underlying cause identified (see Endometriosis, Uterine Fibroids entries)

Referral: gynecology for suspected secondary dysmenorrhoea, red flag features, or primary dysmenorrhoea not responding to first-line NSAID and hormonal measures.

Clinical toolsCalculators

BMI GCS EDD Parkland Formula

Corrected Sodium Corrected Calcium Anion Gap Creatinine Clearance Insulin Calculations qSOFA Wells PE Wells DVT CHA₂DS₂-VASc HAS-BLED CURB-65 Centor/McIsaac

Menorrhagia

Also known as: Heavy menstrual bleeding

Excessive menstrual blood loss (traditionally >80mL/cycle, though clinical definition now based on patient-reported impact on quality of life) interfering with physical, social, emotional, or material quality of life.

PALM-COEIN classification (FIGO) for causes: structural (Polyp, Adenomyosis, Leiomyoma/fibroids, Malignancy/hyperplasia) and non-structural (Coagulopathy, Ovulatory dysfunction, Endometrial, Iatrogenic, Not otherwise classified).

Assess associated features: intermenstrual/postcoital bleeding (structural cause more likely), pelvic pain/pressure (fibroids, adenomyosis), dysmenorrhea, easy bruising/bleeding elsewhere (coagulopathy — particularly if menorrhagia since menarche).

FBC: assess for iron-deficiency anemia

Ferritin: if anemia present
Coagulation screen: if history suggestive (heavy bleeding since menarche, family history, bruising/bleeding elsewhere) — consider von Willebrand disease particularly
TSH: if other hypothyroid features
Pelvic ultrasound (transvaginal preferred): first-line imaging — assesses fibroids, adenomyosis, endometrial thickness, polyps
Endometrial biopsy: if age ≥45, risk factors for endometrial hyperplasia/cancer (obesity, PCOS, tamoxifen use, persistent intermenstrual bleeding), or failed medical management
Hysteroscopy: if focal intrauterine pathology suspected (polyp) needing direct visualization/treatment

Differentials per PALM-COEIN: fibroids, adenomyosis, endometrial polyp, endometrial hyperplasia/malignancy, anovulatory bleeding (PCOS, perimenopause, thyroid dysfunction), coagulopathy (von Willebrand disease), IUD-related, pregnancy complications (always exclude with pregnancy test in reproductive age).

First-line (no structural pathology requiring specific treatment, or as symptom control alongside definitive workup):

Levonorgestrel-releasing IUD (LNG-IUS): most effective medical option, reduces bleeding ~90%, also provides contraception
Tranexamic acid 1g tds during menses (non-hormonal option): reduces blood loss ~50%
NSAIDs (mefenamic acid 500mg tds during menses): reduces flow and dysmenorrhea, modest effect
Combined oral contraceptive: reduces flow, cycle regulation, particularly useful if contraception also desired
Cyclical oral progestogen (norethisterone): short-term option, particularly for dysfunctional bleeding

Fibroids: LNG-IUS if cavity not significantly distorted; GnRH agonists (short-term, pre-surgical shrinkage, menopausal side effects limit duration); uterine artery embolization; myomectomy (fertility-preserving); hysterectomy (definitive, if family complete/severe symptoms refractory to other measures)
Endometrial polyp: hysteroscopic polypectomy
Adenomyosis: LNG-IUS, GnRH agonists, hysterectomy if severe/refractory and family complete
Endometrial hyperplasia: progestogen therapy (oral or LNG-IUS) with surveillance biopsy, hysterectomy if atypical hyperplasia/malignancy or failed medical management
Iron replacement for associated anemia (see Iron Deficiency Anaemia entry)

Referral: gynecology for structural pathology requiring intervention, failed medical management, endometrial hyperplasia/malignancy risk requiring biopsy, or persistent symptoms despite first-line treatment.

Dysmenorrhoea

Overview

Clinical Features

Diagnosis

Management

Overview

Clinical Features

Diagnosis

Management