Reasoning GP · Algorithm · 1-page summary
Abnormal vaginal bleeding
For: heavy, intermenstrual, postcoital or postmenopausal bleeding, unscheduled bleeding on HRT or contraception, and bleeding in early pregnancy (≤12 weeks). Not for: bleeding later in pregnancy (use the pregnancy bleeding pathway). Confirm the source is vaginal, not urinary or rectal.
Core rule: know pregnancy and menopausal status first. A positive test with pain or bleeding is ectopic until excluded, even without risk factors; postmenopausal bleeding, even a single episode, needs endometrial cancer excluded. A normal smear excludes nothing.
0Stop — call 999 now — pulse, BP, postural symptoms, mental state, perfusion
- Shock, ongoing major haemorrhage, collapse, altered consciousness or deterioration → 999 (a heart rate of 100 alone does not define shock)
- Suspected ruptured ectopic: positive test with pain, shoulder-tip pain, syncope, peritonism or significant bleeding → 999 / A&E if unstable or significant pain or bleeding.
- Sepsis: fever >38°C, rigors, tachycardia + PV bleeding (septic miscarriage, endometritis) → 999 Coagulopathy: bleeding from several sites, purpura, anticoagulant overdose → 999
- Retained products (heavy bleeding, clots, recent pregnancy) → Same-day, or 999 if haemodynamically unstable.
1Triage — status decides the pathway
| Status | Next |
|---|---|
| Could be pregnant | Urine βhCG if it would alter management; positive → block 2. |
| Postmenopausal | >12 months after LMP, not an expected sequential-HRT withdrawal bleed → block 2. |
| HRT / contraception | Adherence, interactions, pregnancy and STI risk, time since start or change. |
| Reproductive age | By pattern: HMB, IMB, PCB. |
2Screen — one row is enough
- PMB aged 55+, unexplained, not attributable to HRT → Suspected cancer pathway. Under 55 → consider referral; do not assume the risk is negligible.
- Positive test, stable, possible ectopic → Same-day EPAU / OOH gynae; other stable bleeding ≥6 weeks or uncertain gestation → EPAU.
- Open os, active miscarriage, molar features (hyperemesis, uterus large for dates) → Same-day gynae
- Pelvic or abdominal mass not obviously fibroids, or ascites → Suspected cancer pathway. Cervix consistent with cancer; unexplained vulval lump, ulcer or bleeding → consider it; no smear first.
- IMB/PCB with offensive discharge, pain or fever; PID with systemic upset → Same-day STI/PID or gynae
- Severe or symptomatic anaemia, ongoing heavy bleeding, syncope → Same-day assessment
3Assess — chaperone offered and documented
☐ Pulse, BP, temperature, pallor ☐ Abdomen; speculum for IMB, PCB, persistent or suspicious bleeding; bimanual ☐ FBC for HMB; consider ferritin ☐ Chlamydia/gonorrhoea NAAT by sexual risk ☐ Smear only if due
Scan or hysteroscopy by history (NG88). Not: blind biopsy, routine CA-125, TFTs, hormone tests, progesterone for ectopic.
4Classify — only if the screen is negative
- HMB — defined by impact on quality of life (NG88) → treat.
- IMB / PCB — ectropion, polyp, infection, contraception, cancer → speculum and STI tests; persistent despite assessment → Urgent gynae / colposcopy per local pathway.
- On HRT — first 6 months or 3 months after a change, not heavy or persistent, no major risk factors → BMS pathway; heavy, prolonged, recurrent, late → Urgent investigation
- Perimenopausal (>40, changing cycle) — assess a significant change; persistent IMB, treatment failure or endometrial risk factors → hysteroscopy with sampling.
- Uncertain — say so; record who reviews each result and confirms the referral.
5Treat today — cancer and pregnancy routes first
- HMB, structural cause excluded: LNG-IUS first-line (allow ≥6 cycles); or tranexamic acid, NSAID (mefenamic acid), CHC after UKMEC, or cyclical progestogen. Doses: NICE/SPC, BNF, local formulary.
- Iron deficiency: oral iron once daily or alternate days; recheck Hb at about 4 weeks.
- STI/PID: treat with partner notification. Ectropion → reassure or refer; polyp → refer. No empirical hormones for unexplained IMB.
- PMB atrophy: low-dose vaginal oestrogen only after serious pathology is excluded.
6Refer routinely
- HMB with treatment failure, severe symptoms, suspected pathology, or fibroids for surgical or radiological treatment → gynaecology.
- HMB since menarche with a bleeding history, thrombocytopenia, or anticoagulant-related HMB → haematology.
- High-grade dyskaryosis → colposcopy via the screening programme.
7Never reassure by
- A normal smear: screening is not a diagnostic test.
- A previous normal scan when PMB recurs: re-refer.
- Calling PMB atrophy, or trying vaginal oestrogen, before assessment.
- Age under 55 with PMB.
- A negative urine test or no risk factors when ectopic is suspected.
- A "benign" cause that does not settle with treatment.
8Safety-net — say it, then document it
999 “Call 999 for very heavy bleeding that is not settling, or bleeding with dizziness, fainting, breathlessness or a racing heart; if you are or could be pregnant with severe or one-sided tummy pain, shoulder-tip pain, fainting or heavy bleeding; or fever with shivering or feeling very unwell.”
Same-day “Contact us today for a new fever with bleeding, any bleeding or pain in early pregnancy, bleeding heavier than usual or not settling, or new bleeding after sex once treatment has started.” Same-day assessment: heavy bleeding with dizziness or fainting, severe anaemia symptoms, possible pregnancy, severe pain or rapid worsening; a pad soaked every hour is a pragmatic trigger, not a NICE threshold. Any further bleeding after the menopause → reassess, even after a normal scan. Written safety-netting for early-pregnancy bleeding.
✓Safe to leave primary care only if — all five, documented
Stable; no block 0–2 row applies
Pregnancy and menopausal status recorded
Speculum done for IMB, PCB or suspicious bleeding
Plan, result owner and review date set
Safety-net given and documented
Summary of the full Reasoning GP vaginal bleeding algorithm, which holds the detail, examination, investigations and evidence. Sources: NICE NG12 (updated April 2026), NG88 (updated July 2026), NG126, NG23, NG253; CoSRH; BMS; BSG; NHS Cervical Screening Programme. Clinical reference — follow local pathways and check doses: NICE/SPC, BNF.