Primary dysmenorrhoea

Definition/diagnostic criteria Primary dysmenorrhoea refers to painful menstrual cramps without an identifiable pelvic pathology. It is characterised by cramping pain in the lower abdomen, occurring just before or during menstruation in the absence of other diseases like endometriosis. The pain often radiates to the back and thighs and may be accompanied by nausea, vomiting, diarrhoea, and headache.

Epidemiology Primary dysmenorrhoea is a common condition, impacting an estimated 45-95% of menstruating women, with the highest prevalence in adolescents and young adults. It’s a leading cause of recurrent short-term school or work absenteeism in young women.

Diagnosis

Clinical features: Diagnosis is predominantly clinical. Key features include crampy, lower abdominal pain, starting shortly before or with the onset of menstruation, and lasting 48-72 hours. Original onset is usually six months to a year or so after the menarche. It’s often associated with systemic symptoms like headache, nausea, vomiting, and diarrhoea.

Investigations: No specific investigations are required for the diagnosis of primary dysmenorrhoea. However, if symptoms are atypical or there is a poor response to first-line treatment, further investigation is warranted to exclude secondary causes.

Typical abnormalities: While no abnormalities are found in primary dysmenorrhoea, investigations in cases of suspected secondary dysmenorrhoea might reveal conditions like endometriosis or pelvic inflammatory disease.

Treatment

Pharmacological treatment includes:

• Non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, which are the first-choice due to their dual analgesic and anti-inflammatory properties.
• Paracetamol can be used, though it’s less effective than NSAIDs.
• Hormonal contraceptives like the combined oral contraceptive pill, which reduce menstrual flow and dysmenorrhoea severity.

Non-pharmacological approaches include heat application and TENS (transcutaneous electrical nerve stimulation). Referral to a gynaecologist is recommended for women with severe symptoms not responding to first-line treatments or if a secondary cause is suspected.

Prognosis The prognosis for primary dysmenorrhoea is generally good, with symptoms often improving with age and after childbirth. However, the impact on quality of life and routine activities can be significant, necessitating an empathetic and effective management approach.