Dysmenorrhoea

Definition

• Dysmenorrhoea denotes pain of uterine origin around the time of menstruation; it is typically located in the midline of the lower abdomen and may radiate to the lumbar region or the thighs.

Classification

• Primary dysmenorrhoea: recurrent cyclical lower abdominal pain without underlying disease or anatomical change; it classically begins within about 2 years of menarche, once ovulatory cycles are established.
• Secondary dysmenorrhoea: menstrual pain resulting from underlying pelvic disease or a structural change; it usually begins in adulthood, except when caused by congenital anomalies.

Occurrence & epidemiology

Epidemiology

• Dysmenorrhoea is a common complaint among menstruating women of reproductive age; the primary form accounts for about 90% of cases.
• It interferes with daily activities in 30% or more of women and may lead to absence from school or work.

Aetiopathogenesis

Aetiology and pathogenesis

• In the primary form, increased uterine prostaglandin production, particularly of PGF2α, causes raised uterine tone, high-amplitude contractions and myometrial ischaemia; the fall in progesterone shortly before menstruation increases prostaglandin production.
• The most common cause of the secondary form is endometriosis; other common causes are adenomyosis, uterine fibroids and cervical stenosis, and less common ones include genital tract anomalies, ovarian cysts, previous pelvic inflammatory disease and endometrial polyps.

Clinical features

• The cramping pain begins shortly before or with the onset of bleeding, peaks about 24 hours after the onset of menses and typically resolves within 72 hours.
• Associated symptoms include nausea, vomiting, diarrhoea, headache, dizziness, fatigue and sleep difficulties.
• Women with dysmenorrhoea are more likely to have chronic pelvic pain or other chronic pain conditions.

Diagnosis

• In primary dysmenorrhoea, the physical examination is normal; a focused history and examination are usually sufficient for the diagnosis.
• Features suggesting a secondary form are onset after adolescence, diffuse or constant pain not consistently linked to the onset of menses, and palpable findings such as uterine or adnexal masses, a thickened rectovaginal septum or nodular uterosacral ligaments.
• Transvaginal ultrasound is usually the baseline imaging test, supplemented by sonohysterography or MRI if findings are unclear, for example to characterise anomalies.

Keep learning in the app

Further reading (selection)

1. MSD Manual Professional: Dysmenorrhea
2. StatPearls: Dysmenorrhea (NCBI Bookshelf)
3. Dysmenorrhea and related disorders (F1000Res 2017, PubMed Central)

Cross-references