Adolescent Dysmenorrhoea

Adolescent dysmenorrhoea is painful menstruation in girls and young women aged 10 to 19 years, which is very common, with most cases primary (caused by prostaglandin release) and a minority due to obstructive uterine or vaginal anomalies or early endometriosis. It begins 6 to 24 months after menarche when ovulatory cycles start. It matters because it causes school absence and reduced participation in sport, and a minority of cases hide treatable pelvic anomalies.

Risk factors: early menarche, heavy periods, family history, smoking, high body mass index, depression, stress.

Pain that begins with the very first periods suggests an obstructive anomaly.

Most improve with age, but pain that persists needs evaluation.

Girls have crampy lower abdominal pain at the start of the period lasting 1 to 3 days, with nausea, vomiting, headache and fatigue. Girls with obstruction have severe cyclical pain from the first periods, with little or no bleeding and a pelvic or vaginal mass.

Normal examination between periods.

Bulging hymen or absent vaginal opening in an obstructive anomaly.

Differential diagnosis: primary dysmenorrhoea, imperforate hymen, transverse vaginal septum, noncommunicating uterine horn, endometriosis, pelvic inflammatory disease, ovarian cyst, ectopic pregnancy, irritable bowel syndrome, urinary tract infection, abuse.

Complications: school and sport absence, depression and anxiety, overuse of analgesics, haematocolpos and retention, endometriosis, reduced quality of life.

The approach is a sensitive history and examination, with imaging for severe or atypical pain.

History of menarche age, onset of pain, severity, school absence, sexual history and safety (private interview); pain score.

Abdominal examination, and external genital examination for hymen and vaginal opening; pelvic examination only when sexually active or when needed.

Urine hCG; chlamydia and gonorrhoea tests if sexually active.

Pelvic ultrasound (and MRI if needed) for pain from the first periods, severe pain, poor response to treatment or pelvic mass; laparoscopy for persistent pain on treatment.

The principle is weight-based NSAIDs started at the first sign of pain, with hormonal treatment for failure, and imaging or surgery for anomalies.

• Supportive: reassurance and education; heat pack; regular exercise; adequate sleep; school support and a plan for pain days; pain diary; confidential discussion of safety and contraception.
• Pharmacological: ibuprofen 5 to 10 mg/kg oral per dose 8-hourly with food (maximum 400 mg per dose and 1200 mg daily), started at the first sign of pain or bleeding and continued for 2 to 3 days; mefenamic acid 500 mg oral 8-hourly with food for 3 days in girls aged 12 years and above; naproxen 250 mg oral 8-hourly with food for 3 days in girls weighing over 40 kg; paracetamol 15 mg/kg oral per dose 6-hourly (maximum 1 g per dose and 60 mg/kg daily) if NSAIDs are contraindicated; for failure after 3 months of NSAIDs or if contraception is wanted: combined oral contraceptive pill with ethinylestradiol 30 micrograms and levonorgestrel 150 micrograms oral once daily for 21 days then 7 days free (or continuous), or depot medroxyprogesterone 150 mg IM every 13 weeks, or levonorgestrel intrauterine system 52 mg for 5 years.
• Procedures: hymenotomy for imperforate hymen; excision of a vaginal septum; resection of a noncommunicating uterine horn; diagnostic laparoscopy for pain that fails treatment.
• Special groups: girls with asthma sensitive to NSAIDs, kidney disease or peptic ulcer use paracetamol and hormonal treatment; girls with migraine with aura, hypertension or previous clot avoid combined pills and use progestogen-only methods; sexually active girls have contraception, infection testing and counselling, with safeguarding review when abuse is suspected.
• Red flags: pain from the very first period, severe pain with no or minimal bleeding, pelvic mass, vomiting with collapse, fever, positive pregnancy test, pain not responding to 3 months of treatment, suspected abuse.
• Follow-up: review at 3 months with pain score and school attendance; ultrasound and gynaecology referral for failure of 2 treatments; review at 6 and 12 months; transition to adult care.