Dysmenorrhoea

Definition | Aetiology | Pathophysiology | Symptoms and Signs | Management | References

Definition

Dysmenorrhoea refers to painful menstrual cramps that occur immediately before or during menstruation. It is classified into two types: primary dysmenorrhoea (without an underlying medical condition) and secondary dysmenorrhoea (associated with conditions such as endometriosis or fibroids).

Aetiology

Primary dysmenorrhoea is typically caused by increased production of prostaglandins during menstruation, leading to increased uterine contractions and pain. Secondary dysmenorrhoea may be due to various gynaecological conditions such as endometriosis, adenomyosis, or pelvic inflammatory disease.

Pathophysiology

Prostaglandins produced by the endometrium during menstruation cause the uterine muscles to contract more strongly. These contractions reduce blood flow to the uterus, leading to ischaemia and pain. In secondary dysmenorrhoea, the pain is related to the underlying gynaecological pathology, such as inflammation or abnormal growths.

Symptoms and Signs

• Lower abdominal pain, often cramping or throbbing in nature.
• Pain that radiates to the lower back or thighs.
• Nausea, vomiting, or diarrhoea may accompany the pain.
• Headache and dizziness.
• Fatigue.

Management

Management of dysmenorrhoea depends on whether it is primary or secondary and the severity of the symptoms:

Primary Dysmenorrhoea

• NSAIDs (Non-Steroidal Anti-Inflammatory Drugs): First-line treatment includes NSAIDs, which reduce prostaglandin production. Commonly used NSAIDs include:
  • Ibuprofen: Typically 200-400 mg taken every 4-6 hours as needed.
  • Naproxen: 500 mg initially, followed by 250 mg every 6-8 hours as needed. Naproxen is often preferred due to its longer duration of action.
  • Mefenamic Acid: 500 mg initially, followed by 250 mg every 6 hours as needed. Mefenamic acid is particularly useful when NSAIDs alone are insufficient.
• Hormonal Contraceptives: Combined oral contraceptive pills (COCPs) can be effective in reducing menstrual pain by suppressing ovulation and reducing the thickness of the endometrium. The combined oral contraceptive pill is often prescribed if NSAIDs are not effective.
  • Oral Contraceptive Pill: Taken daily to prevent ovulation and reduce menstrual pain.
  • Progestogen-only Pill: May be an alternative for women who cannot take oestrogen.
  • Intrauterine System (IUS, e.g., Mirena Coil): A hormone-releasing coil that can reduce or eliminate menstrual bleeding and pain over time.
• Antifibrinolytic Agents: Tranexamic acid is used to reduce heavy menstrual bleeding, which can help reduce pain associated with excessive blood loss.
  • Tranexamic Acid: 1-1.5 g three times daily for up to 4 days during menstruation.

Secondary Dysmenorrhoea

Treatment is directed at the underlying cause, such as managing endometriosis with hormonal therapy or surgery. Referral to a gynaecologist is recommended for further evaluation and treatment in these cases.

When to Refer to a Gynaecologist

• If symptoms do not improve with first-line treatments, including NSAIDs and hormonal therapy.
• If there is a suspicion of secondary dysmenorrhoea due to underlying conditions such as endometriosis or fibroids.
• If the pain is severe or associated with other concerning symptoms such as abnormal bleeding, significant weight loss, or infertility.
• If there is a failure to respond to treatment, consider referring for further investigation, including imaging (e.g., ultrasound) or diagnostic laparoscopy.

References

1. NHS (2024) Dysmenorrhoea. Available at: https://www.nhs.uk/conditions/painful-periods/ (Accessed: 24 June 2024).
2. National Institute for Health and Care Excellence (2024) Menstrual Conditions: Management of Dysmenorrhoea. Available at: https://cks.nice.org.uk/topics/dysmenorrhoea/ (Accessed: 24 June 2024).
3. British Medical Journal (2024) Management of Dysmenorrhoea. Available at: https://www.bmj.com/content/350/bmj.h1857 (Accessed: 24 June 2024).

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