Acute severe uterine bleeding

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Acute severe uterine bleeding is bleeding sufficient to require urgent intervention because of volume, trajectory, symptoms or physiological effect. It can be a sudden first episode or an acute worsening of chronic HMB. Ask how many products are saturated and whether there is continuous flow or clots, but do not use pad counts as the sole severity measure. Record syncope, breathlessness, chest pain, palpitations, pain, fever, pregnancy possibility, recent birth or procedure, medicines, bleeding history and known fibroids or endometrial disease.

Resuscitation and diagnosis occur together. Perform ABCDE, call senior gynaecology and anaesthesia early, establish two large-bore venous lines, monitor continuously and keep the patient warm. Send full blood count, group-and-save or crossmatch, renal and liver profile and coagulation; major haemorrhage commonly adds fibrinogen, gas, lactate and repeated point-of-care testing. Activate the institution’s major-haemorrhage protocol for uncontrolled bleeding or shock, using balanced blood-component support directed by the protocol and laboratory or viscoelastic findings.

One haemoglobin value underestimates early acute loss because plasma and red-cell volumes fall together before redistribution. Use perfusion, ongoing bleeding, comorbidity, serial values and the time to definitive control. NICE NG24 uses restrictive red-cell thresholds for many stable non-bleeding adults, often 70 g/L, but this threshold does not govern active major haemorrhage. Transfuse according to clinical need and protocol, reassessing calcium, temperature, coagulation and volume overload risk.

Exclude pregnancy and localise bleeding. A positive hCG with pain or instability needs urgent ectopic or pregnancy-loss management. If pregnancy is not responsible and the patient can tolerate examination, inspect for vulval, vaginal or cervical trauma and visualise whether blood emerges from the cervical os. Bimanual examination may identify uterine enlargement or tenderness but should not delay ultrasound or theatre. In later pregnancy, digital examination is withheld until placental location is safely addressed by the obstetric team.

Medical haemostasis is most useful when physiology is stable enough to allow time. Tranexamic acid inhibits fibrinolysis and can reduce menstrual blood loss. The UK oral product regimen for menorrhagia is 1 g three times daily for no more than four days, beginning when heavy bleeding starts; adjust in renal impairment and avoid where active or important prior thrombosis makes treatment unsafe. Hospital intravenous use follows the product and local haemorrhage protocol, avoiding rapid administration that can cause hypotension.

Progestogen can stabilise anovulatory endometrium. Norethisterone 5 mg orally three times daily for 10 days is a licensed regimen for dysfunctional uterine bleeding; withdrawal bleeding usually follows stopping. It is not contraception. Exclude pregnancy and avoid in current or prior important venous thromboembolism, arterial thrombosis, severe liver disease or unexplained bleeding not yet assessed, using the SmPC and patient-specific risks. Combined hormonal high-dose regimens have substantial contraindications and should follow a senior local protocol rather than improvised dosing.

Continued loss requires source control. Options depend on cause, anatomy, stability and fertility priorities: remove retained pregnancy tissue, hysteroscopically treat a focal cavity lesion, use intrauterine balloon tamponade as a temporising specialist measure, embolise uterine arteries for selected fibroid or vascular bleeding, or perform laparoscopy, laparotomy or hysterectomy. Blind curettage is not a universal treatment for non-pregnant abnormal bleeding and can miss or injure. Do not repeat medicines while transfer, interventional radiology or theatre is being delayed.

After haemostasis, establish why the episode occurred. Review pregnancy outcome, fibroid or polyp imaging, endometrial risk and histology, ovulatory pattern, bleeding disorder and anticoagulants. Decisions about holding or reversing anticoagulation are multidisciplinary because thrombosis risk persists. Replace iron, repeat blood count, explain expected bleeding after hormonal treatment and give direct instructions for recurrent flooding, pain, faintness, fever or breathlessness.

Key points

Estimate physiological severity before counting pads: observations, consciousness, perfusion, urine output, ongoing visible loss and comorbidity determine urgency.
Ask last normal period and obtain a consented pregnancy test early, but never delay resuscitation or theatre for an unstable suspected pregnancy haemorrhage.
Confirm the source with focused abdominal and consented speculum examination when stable enough; avoid digital vaginal examination in later-pregnancy bleeding until placenta praevia is addressed.
Obtain two large-bore cannulas, full blood count, group-and-save or crossmatch, renal and liver profile, coagulation and fibrinogen under the major-haemorrhage pathway, with venous gas and lactate when unwell.
Haemoglobin can remain initially normal in acute blood loss; transfusion and haemorrhage activation are driven by physiology, ongoing loss and anticipated control, not a delayed number alone.
For a haemodynamically stable non-pregnant patient without contraindication, tranexamic acid and an appropriate hormonal regimen can reduce bleeding while cause and definitive follow-up are arranged.
A licensed oral norethisterone regimen for dysfunctional uterine bleeding is 5 mg three times daily for 10 days, but exclude pregnancy and major thrombotic or hepatic contraindications before use.
Oral tranexamic acid for heavy menstrual bleeding is 1 g three times daily for up to four days from the onset of heavy loss; renal impairment and thrombotic history modify safety.
If bleeding persists or the patient is unstable, senior options include uterine tamponade, hysteroscopy with treatment, evacuation for retained tissue, uterine artery embolisation or surgery according to cause and fertility goals.
After control, treat iron deficiency, establish the PALM-COEIN cause, review anticoagulation collaboratively and provide a written plan for recurrence.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Pregnancy and tissue separation

Ectopic rupture, miscarriage, retained pregnancy tissue and placental disease can produce sudden genital or intraperitoneal haemorrhage.

Endometrial or structural bleeding

Anovulatory endometrium, submucosal fibroid, polyp, hyperplasia and malignancy can expose broad or unusually fragile vascular surfaces.

Haemostatic impairment

Inherited coagulation disease, thrombocytopenia, liver dysfunction and anticoagulants reduce clot formation or stability and amplify uterine loss.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Circulating volume loss
Rapid external or internal haemorrhage reduces preload and tissue perfusion, triggering tachycardia and vasoconstriction before hypotension and organ injury develop.
2
Unstable endometrial vessels
Irregular hormonal exposure or focal cavity disruption prevents coordinated vasoconstriction and repair, allowing persistent bleeding from the uterine surface.
3
Consumption and dilution
Continuing haemorrhage, fluid replacement and component imbalance can lower platelets, fibrinogen and clotting factors, worsening bleeding in a self-reinforcing cycle.
4
Oxygen delivery failure
Reduced blood volume and red-cell mass eventually impair oxygen delivery, causing lactate rise, myocardial strain, kidney injury and altered consciousness.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Compensated blood lossRed flag

Tachycardia, pallor, dizziness and delayed refill can precede hypotension and a haemoglobin fall, especially in a young otherwise healthy patient.

Decompensated haemorrhageRed flag

Hypotension, confusion, oliguria, cool peripheries, collapse or rising lactate indicates inadequate perfusion and demands protocolled resuscitation and control.

Pregnancy-related source

Amenorrhoea, positive hCG, unilateral pain, tissue passage or recent pregnancy redirects care to ectopic, miscarriage, retained products or postpartum causes.

Structural source

Known cavity-distorting fibroid, polyp, enlarged uterus or focal lesion can produce sudden heavy loss and may need hysteroscopic, radiological or surgical control.

Coagulopathic amplification

Anticoagulants, thrombocytopenia, liver disease or inherited bleeding disorder magnifies uterine loss and may cause oozing from venepuncture or other sites.

Septic bleeding

Fever, uterine tenderness, offensive discharge and recent birth or instrumentation suggests infection requiring antibiotics and source assessment as well as haemostasis.

Red flags requiring action

A positive or uncertain pregnancy test changes the emergency differential to ectopic pregnancy, miscarriage, retained tissue, trophoblastic or placental bleeding and requires the appropriate obstetric pathway.
Tachycardia, hypotension, narrow pulse pressure, delayed capillary refill, oliguria, altered mentation or rising lactate signals tissue hypoperfusion even before haemoglobin falls.
Severe unilateral pain, peritonism, shoulder-tip pain or collapse raises intraperitoneal bleeding and should not be managed as isolated heavy menstruation.
Fever, offensive discharge, recent uterine procedure, postpartum state or marked tenderness raises uterine infection or sepsis and requires antimicrobial and source-control planning.
Anticoagulant exposure, thrombocytopenia, liver disease or inherited bleeding disorder may amplify loss and needs urgent haematology-informed reversal or replacement without delaying local control.
Bleeding continuing despite resuscitation and appropriate medication requires immediate procedural escalation rather than repeated outpatient-dose prescriptions.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Serial observations and perfusionFirst step
Why
Determine haemorrhage severity and response to resuscitation in real time.
Interpretation and limitations
Trend pulse, blood pressure, respiratory rate, consciousness, capillary refill, temperature and urine; deterioration overrides one normal blood result.
02
Pregnancy test and early-pregnancy assessment
Why
Identify pregnancy-related causes requiring different imaging and treatment.
Interpretation and limitations
Positive hCG does not locate pregnancy. Use urgent transvaginal ultrasound and senior assessment; instability may require surgery before a diagnostic scan.
03
Full blood count and serial haemoglobin
Why
Assess anaemia, platelets and evolving loss while blood support is prepared.
Interpretation and limitations
An initially normal haemoglobin does not exclude major acute haemorrhage. Serial change is interpreted with fluids, transfusion and ongoing bleeding.
04
Crossmatch and coagulation profile
Why
Prepare red cells and identify or monitor haemostatic derangement during substantial loss.
Interpretation and limitations
Use the local major-haemorrhage bundle, commonly including fibrinogen and repeated testing. Anticoagulant-specific assays and reversal need specialist input.
05
Speculum examination and pelvic ultrasound
Why
Localise genital bleeding and identify pregnancy tissue, fibroid, polyp, endometrial or adnexal disease when stable.
Interpretation and limitations
Do not delay resuscitation. Ultrasound morphology informs the intervention, but ongoing haemorrhage may require direct hysteroscopy or surgery.
06
Endometrial or operative histology
Why
Diagnose hyperplasia, malignancy, retained tissue or focal pathology after immediate control.
Interpretation and limitations
Obtain tissue through the appropriate pregnancy or hysteroscopy pathway. Acute control does not complete cancer-risk assessment.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Ectopic or miscarriage bleeding

Pregnancy-related loss can resemble a heavy period, while unilateral pain, syncope and an empty uterus increase ectopic concern.

Genital tract trauma

Vaginal or cervical laceration after sex, assault, birth or instrumentation can cause brisk bleeding independent of the endometrium.

Urinary or gastrointestinal haemorrhage

Haematuria and rectal bleeding may be misidentified as vaginal when loss is profuse; examination and catheter or rectal assessment localise it.

Intra-abdominal catastrophe

Ruptured ovarian cyst, torsion-associated bleeding or non-gynaecological abdominal haemorrhage can cause collapse with little external loss.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01Unstable bleedingResuscitate and control the source in parallelFirst stepUterine bleeding accompanies shock, hypoperfusion, ongoing flooding or rapid deterioration.

1Activate ABCDE, major-haemorrhage and senior gynaecology and anaesthetic support, establish large-bore access, warm the patient and send urgent crossmatched bloods.
2Establish pregnancy status and likely anatomical source without delaying transfer to theatre, embolisation or pregnancy-specific surgery when clinically compelling.
3Use blood components, tranexamic acid or reversal under the local protocol and move to mechanical or operative haemostasis if loss continues.

02Stable non-pregnant bleedingUse time-limited medical haemostasis while defining causeBleeding is substantial but observations and perfusion remain stable and pregnancy is excluded.

1Obtain full blood count, group-and-save and focused examination, and review thrombosis, liver, kidney, contraceptive and medicine factors.
2Offer oral tranexamic acid and an appropriate hormonal regimen such as licensed norethisterone when indicated and safe, with exact duration and stop advice.
3EscalationArrange timely ultrasound, hysteroscopy or specialist review and escalate immediately if flooding, pain, symptoms or physiology worsens despite treatment.

03Failed medical controlChoose tamponade, radiology or surgeryBleeding remains heavy, recurs immediately or causes physiological compromise despite suitable medicines.

1Summon senior gynaecology, anaesthesia and interventional radiology as locally available and reassess cause, fertility priorities and operative risk.
2Use a cause-matched intervention such as hysteroscopic treatment, evacuation, balloon tamponade, uterine artery embolisation or operative surgery.
3DefinitiveContinue resuscitation and laboratory-guided correction through definitive control, documenting residual fertility and follow-up implications.

04After controlPrevent recurrence and restore ironDefinitiveAcute bleeding has stopped or reduced sufficiently for definitive planning.

1Reconcile the final cause, pregnancy outcome, imaging, histology, coagulation and medicine contribution and name unresolved questions.
2Treat iron deficiency, plan ongoing HMB therapy and review anticoagulation with the relevant prescriber rather than leaving it stopped indefinitely.
3Repeat blood count and provide direct return triggers and a specialist follow-up date appropriate to the severity and intervention.

Key medicines and prescribing safety2 treatments · regimens, roles and cautions

Reduces fibrinolysis and menstrual blood loss in a stable non-pregnant patient while investigation or definitive treatment is arranged.

Tranexamic acid tablets

Give 1 g orally three times daily for up to four days, starting when heavy bleeding begins; do not exceed the product maximum and reduce the regimen in renal impairment.

Avoid with active thromboembolic disease and assess important thrombotic history, haematuria and combined hormonal use; visual symptoms require cessation and urgent review. Intravenous dosing belongs to the local haemorrhage protocol.

Progestogenic endometrial stabilisation can arrest non-pregnant anovulatory or dysfunctional uterine bleeding when selected after assessment.

Norethisterone tablets

Give 5 mg orally three times daily for 10 days for licensed dysfunctional uterine bleeding; explain that withdrawal bleeding usually occurs within several days after the course ends.

Exclude pregnancy and avoid with current or important previous venous or arterial thrombosis, severe liver disease and unexplained malignancy-risk bleeding; it is not contraceptive and the SmPC governs interactions.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Haemorrhagic shock

Untreated volume loss progresses to tissue hypoxia, acidosis, hypothermia, coagulopathy, organ failure, cardiac arrest and death.

Severe anaemia

Reduced oxygen-carrying capacity causes exertional or resting symptoms, myocardial ischaemia and prolonged recovery even after active bleeding stops.

Treatment complications

Transfusion reactions, thrombosis, medication toxicity, perforation, infection and fertility-altering surgery require carefully risk-balanced escalation and monitoring.

Recurrent unresolved bleeding

Failure to identify fibroid, endometrial disease, coagulopathy or medicine contribution leads to repeated emergency attendance and cumulative iron loss.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

During active loss trend physiology, visible bleeding, urine output, haemoglobin, platelets, coagulation, fibrinogen, calcium and temperature at intervals set by the haemorrhage protocol.
After oral treatment begins, reassess within the urgency dictated by bleeding and symptoms; continued flooding is treatment failure, not a reason to wait for course completion.
Record units and products transfused, adverse reactions, thrombosis risk and the laboratory or clinical target used for continued support.
Track pregnancy, imaging, hysteroscopy and histology findings until the bleeding mechanism and recurrence plan are documented.
Repeat full blood count and iron assessment after discharge and confirm that anticoagulant and hormonal stop or restart decisions have an accountable prescriber.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Haemoglobin lags haemorrhage

A patient can lose a dangerous circulating volume before dilution makes the laboratory concentration fall, so physiology and trajectory lead.

Pregnancy changes the procedure

The same visible bleeding may require ectopic surgery, miscarriage care or placental management rather than non-pregnant endometrial treatment.

Medicine buys controlled time

Antifibrinolytic or hormonal treatment is useful only while monitoring and definitive planning continue; it must not become a barrier to source control.

Anticoagulation has two hazards

Ongoing haemorrhage and thrombosis from abrupt interruption compete, requiring indication-specific reversal and restart decisions with the relevant specialist.

Control is not diagnosis

Stopping an episode does not explain it; structural, endometrial, ovulatory and haemostatic causes still need risk-matched follow-up.

11Common pitfallsFrequent interpretation and management errors.

01
Waiting for haemoglobin to fall before recognising clinically major acute blood loss.
02
Managing a positive pregnancy test with a routine non-pregnant heavy-period regimen.
03
Repeating oral tranexamic acid while a deteriorating patient needs haemorrhage activation and procedural control.
04
Using norethisterone without excluding pregnancy or checking thrombotic and hepatic contraindications.
05
Stopping anticoagulation indefinitely without assessing its indication, reversal need and safe restart plan.
06
Discharging after bleeding slows without resolving anaemia, cause, histology ownership and recurrence instructions.