RCGP SCA Algorithm — UK Primary Care
Heavy menstrual bleeding (HMB) is defined by its effect on the woman's quality of life, not by a measured volume (NICE NG88). Before classifying it as HMB, exclude the emergency, pregnancy and bleeding that is not menstrual at all.
NICE NG88 deliberately defines HMB by its impact on physical, emotional, social and material quality of life, and says measuring blood loss is not needed. The red flags above are not HMB at all, or they are HMB with a dangerous cause: pregnancy complications, endometrial, cervical and ovarian cancer, and colorectal cancer presenting as iron deficiency.
Postmenopausal bleeding is a different presentation: NG12 (updated April 2026) asks for a suspected cancer pathway referral at 55 or over when it is unexplained and not due to HRT, and to consider referral under 55. Von Willebrand disease is the commonest inherited bleeding disorder and is substantially under-diagnosed in women with lifelong HMB.
NG88 is history-led: the history decides whether examination and investigations are needed at all, and whether treatment can start today. Distinguishing regular heavy bleeding from irregular, intermenstrual or postcoital bleeding is the single most important step, because the latter needs a look at the cervix and often imaging or hysteroscopy rather than empirical treatment alone.
NG88 moved away from routine examination and ultrasound for all women: in uncomplicated HMB treatment can start on the history. Examination and imaging are targeted at the features that suggest structural or sinister pathology. Hysteroscopy is preferred to ultrasound alone where endometrial pathology is suspected, because it allows direct sampling of focal lesions.
Iron deficiency is very common in HMB and frequently under-treated; NICE removed its advice against routine ferritin testing in July 2026 for this reason. Hormone profiles do not help: cycle hormones are normal in most women with HMB and do not guide treatment.
Classifying the bleeding as structural (polyp, adenomyosis, leiomyoma, malignancy/hyperplasia) or non-structural (coagulopathy, ovulatory, endometrial, iatrogenic, not yet classified) follows the FIGO PALM-COEIN approach. For most women in primary care no structural cause is found and treatment starts on the history.
Most HMB is managed in primary care. Referral is for the woman whose bleeding has a sinister or structural cause, who has not responded to first-line treatment, or who wants to consider surgical options (endometrial ablation, myomectomy, uterine artery embolisation, hysterectomy) — NG88 asks that these are discussed rather than offered only after failed medication.
Next steps: see Heavy menstrual bleeding · Iron deficiency & iron-deficiency anaemia · Contraception
NG88 makes the 52 mg LNG-IUS the first treatment to consider when there is no structural abnormality, or only fibroids under 3 cm not distorting the cavity, or suspected adenomyosis; it is the most effective medical option for most women. If it is unsuitable or declined, non-hormonal (tranexamic acid, NSAIDs) and hormonal (combined hormonal contraception, cyclical oral progestogens) options are offered. Treatment should start at the first consultation, in parallel with any investigation.
The hormonal options are contraceptive and cannot be used while trying to conceive, so the pregnancy-plans question comes first. Iron deficiency is treated alongside: correcting it often improves fatigue more than controlling the bleeding.
NG88 emphasises shared decision-making: the woman's priorities (contraception, fertility, avoiding hormones, avoiding surgery) determine the choice between options of similar effectiveness, and a diary gives both of you an objective way to judge the response.
Treatment failure and persistent anaemia are the commonest reasons for missed structural pathology; planned review at about 3 months, with the diary and the FBC, catches both. Women using tranexamic acid or combined hormonal contraception should know the symptoms of VTE.