What criteria should I use to decide when to refer a patient with dysmenorrhoea for further investigation?

Criteria for referral of a patient with dysmenorrhoea for further investigation include the presence of red flags suggesting a serious secondary cause. Refer urgently if any of the following are present: a positive pregnancy test with pelvic pain, tenderness, and vaginal bleeding (possible ectopic pregnancy); ascites or a pelvic/abdominal mass not clearly due to fibroids; an abnormal cervix on examination; persistent intermenstrual or postcoital bleeding without features of pelvic inflammatory disease; or an ultrasound scan suggestive of cancer.

Consider referral if menstrual pain begins after several years of painless periods, as this may indicate secondary causes such as endometriosis, fibroids, or pelvic inflammatory disease.

For primary dysmenorrhoea, if symptoms are severe and do not respond to initial treatment within 3–6 months, or if there is doubt about the diagnosis, refer to a gynaecologist for further assessment.