Dysmenorrhoea and the PMS–PMDD spectrum: prostaglandin-mediated period pain and the luteal-phase psychiatric disorder

A 16-year-old misses school every month with cramping pain, and a 34-year-old dreads the week before her period because she becomes a person she does not recognise. The first has primary dysmenorrhoea; the second has PMDD. The two sit on the same clinic list because both are driven by the menstrual cycle — and both are under-recognised, under-treated and examinable. This topic covers the prostaglandin pathway of primary dysmenorrhoea, the causes of secondary dysmenorrhoea, the DSM-5 PMDD criteria reproduced verbatim, and the evidence behind every step of the ladder.[1][6][8]

Overview and definition

Dysmenorrhoea is painful menstrual cramping of uterine origin. It is the most common menstrual complaint and, in up to 20% of women, is severe enough to interfere with daily activities.[6]

• Primary dysmenorrhoea — painful menstruation in the absence of pelvic pathology. It usually begins within 6 to 12 months of menarche, with spasmodic cramping lower abdominal pain starting just before or at the onset of menstruation and peaking in the first 24 to 72 hours, often with nausea, vomiting, diarrhoea, fatigue and headache.[6][7]
• Secondary dysmenorrhoea — dysmenorrhoea associated with an organic or structural cause. It develops years after menarche (often in the third or fourth decade), is frequently progressive, may begin days before menses, and is accompanied by other features of the underlying disease (dyspareunia, abnormal bleeding, subfertility).[6]

The premenstrual disorders occupy a separate but adjacent spectrum, defined by timing: psychological and physical symptoms that develop in the luteal phase, cause functional impairment, and resolve shortly after the onset of menses. They are subdivided into premenstrual syndrome (PMS) and the more severe premenstrual dysphoric disorder (PMDD).[8][10]