Vaginal bleeding in late pregnancy

Vaginal bleeding in late pregnancy (antepartum haemorrhage) is bleeding from the genital tract after 20 weeks of gestation and before the birth of the baby. Many services apply the formal definition from 24 weeks, the usual limit of viability.

The main clinical points:

• Detect haemodynamic compromise early. A pregnant woman keeps her blood pressure until a large volume has been lost.
• Avoid digital vaginal examination until placenta praevia is excluded.
• Assess foetal wellbeing.
• Recognise placental abruption, placenta praevia, vasa praevia and uterine rupture, which threaten both lives.

Clinical relevance. Antepartum haemorrhage is a leading cause of maternal haemorrhage, preterm birth, perinatal death and maternal death. Abruption causes consumptive coagulopathy. Vasa praevia can exsanguinate the foetus within minutes of membrane rupture.

Physiology. Blood volume rises by 40 to 50% in pregnancy, so tachycardia and hypotension appear late, after 1 to 1.5 L of loss. Uterine blood flow at term is about 500 to 700 mL/min, so loss can be rapid. Fibrinogen is normally raised (4 to 6 g/L at term).

Mechanisms.

• Praevia: the placenta lies over or near the internal os. Bleeding follows formation of the lower segment and cervical effacement.
• Abruption: haemorrhage into the decidua basalis separates a normally sited placenta, forming a retroplacental clot. Blood either escapes (revealed) or is retained (concealed).
• Vasa praevia: unprotected foetal vessels cross the membranes over the os and tear when the membranes rupture.

Classification by amount of loss. Spotting (staining only), minor (under 50 mL), major (50 to 1000 mL without shock) and massive (over 1000 mL or clinical shock). The visible loss often underestimates true loss, especially in concealed abruption.

Classification by cause. Placenta praevia (placenta covering the os) and low lying placenta (edge within 20 mm of the os); placental abruption; vasa praevia; uterine rupture; marginal sinus bleed; genital tract lesion; show of labour; and bleeding of unknown origin.

Abruption severity is graded:

• Grade 1: mild, no foetal compromise
• Grade 2: foetal compromise, tense uterus
• Grade 3: foetal death, with 3a lacking and 3b having coagulopathy

Key distinctions.

• Painless, fresh, recurrent bleeding with a soft uterus and a high or malpresenting foetus suggests praevia.
• Painful bleeding with dark blood, a hard tender uterus and foetal compromise suggests abruption.
• Bleeding at membrane rupture with foetal bradycardia suggests vasa praevia.

The pain distinction is unreliable. Concealed abruption may cause pain with little or no visible bleeding, and shock out of proportion to visible loss.

History

• Gestation and dates, estimated due date, number of foetuses.
• Bleeding: onset, amount (pads each hour), colour, clots, relation to intercourse, trauma or membrane rupture, previous episodes.
• Pain: onset, constant or intermittent, site, relation to contractions, back pain, tightening of the abdomen.
• Foetal movements: reduced or absent.
• Symptoms of shock or compromise: dizziness, syncope, pallor, thirst, palpitations; headache, visual disturbance, epigastric pain, swelling (pre eclampsia); fever and offensive discharge (chorioamnionitis).
• Placental location on the anomaly scan, known low lying placenta or praevia, and previous bleeding.
• Risk factors for praevia and accreta: previous caesarean section (risk rises with each), previous uterine surgery or curettage, assisted conception, multiple pregnancy, smoking, maternal age over 35, multiparity, previous praevia.
• Risk factors for abruption: hypertension or pre eclampsia, previous abruption, abdominal trauma (including falls, road accidents and domestic violence), smoking, cocaine or amphetamine use, thrombophilia, preterm prelabour rupture of membranes, polyhydramnios with sudden decompression, multiple pregnancy, uterine fibroids, age over 35, low body mass index.
• Past medical history: bleeding disorders, anticoagulation, anaemia, hypertension, diabetes, sickle cell disease, previous postpartum haemorrhage.
• Antenatal care: rhesus status, antibodies, haemoglobin, cervical screening, last scan.
• Social: intimate partner violence, substance use, distance to a hospital with blood and theatre.

Examination

• Vital signs: pulse, blood pressure, respiratory rate, temperature, oxygen saturation, urine output, capillary refill. Calculate the shock index (pulse divided by systolic pressure); over 0.9 indicates significant haemorrhage even when the blood pressure is normal.
• Pallor, level of consciousness, cold peripheries.
• Abdomen: uterine tone (soft, firm, woody hard), tenderness, fundal height against dates, lie and presentation, engagement of the head (a high or oblique presenting part suggests praevia), contractions, scars.
• Foetal heart: auscultation or continuous cardiotocography from viability; ultrasound to confirm cardiac activity if not found.
• Visible loss: inspect pads and vulva.
• Speculum examination only when placenta praevia has been excluded by ultrasound or in an emergency where praevia is already known: assess cervical dilatation, local lesions (ectropion, polyp, carcinoma, warts, infection) and amount of blood.
• Digital vaginal examination only after praevia and vasa praevia are excluded, ideally by a senior clinician, and in theatre when praevia is possible.
• Bedside tests: haemoglobin by point of care meter, urine dipstick for protein, bedside clotting test (a 10 mL sample of venous blood in a plain tube should clot in under 7 minutes with a firm clot; failure suggests fibrinogen under about 2 g/L).

Red flags

• Shock index over 0.9, systolic pressure under 100 mmHg, pulse over 100 beats/min, altered consciousness, pallor, cold peripheries, or oliguria under 30 mL/h.
• Rigid, tender, woody hard uterus; constant severe pain; uterus enlarging.
• Abnormal cardiotocography (reduced variability, late decelerations, bradycardia, sinusoidal pattern) or absent foetal heart.
• Bleeding at the moment of membrane rupture (vasa praevia).
• Previous caesarean section with a praevia (accreta spectrum), or scar pain, loss of presenting part and foetal bradycardia (uterine rupture).
• Pre eclampsia or severe hypertension.
• Bleeding after trauma, even minor.
• Signs of coagulopathy: oozing from cannula sites, petechiae, bleeding gums.
• Rhesus negative blood group, or unbooked pregnancy, or inability to reach a hospital quickly.

Special groups. Trauma: abruption can follow minor trauma and may be delayed up to 24 hours.

Women who decline blood: plan early with cell salvage, tranexamic acid and intravenous iron. Obesity: difficult ultrasound and abdominal examination. HIV infection: avoid invasive procedures if possible and continue antiretroviral therapy. Region specific: severe anaemia, hookworm and malaria reduce reserve, and delay in transport is a major cause of death.

Organised by site of origin. Each cause is common unless marked serious or uncommon. Placental causes

• Serious: placental abruption (revealed, concealed or mixed).
• Serious: placenta praevia and low lying placenta.
• Serious: placenta accreta spectrum (accreta, increta, percreta).
• Marginal sinus bleed (marginal placental separation without full abruption).
• Placental polyp and chorioangioma (uncommon).
• Circumvallate placenta.

Foetal vessel causes

• Serious: vasa praevia (types I and II, including velamentous cord insertion and succenturiate lobe).
• Ruptured velamentous cord vessel.

Uterine causes

• Serious: uterine rupture (scarred or unscarred uterus, obstructed labour, trauma, oxytocin).
• Show of labour and preterm labour.
• Uterine fibroids with degeneration or retroplacental fibroid.
• Cornual or interstitial pregnancy that has continued (rare), uterine anomaly.
• Chorioamnionitis.

Cervical and vaginal causes

• Cervical ectropion (common in pregnancy), cervical polyp, decidual change.
• Cervicitis and vaginitis (trichomoniasis, chlamydial, gonococcal and herpes infection), genital warts.
• Serious: cervical cancer.
• Vaginal varices and vulval varices.
• Vaginal, vulval or cervical trauma, including after intercourse or sexual assault.
• Foreign body.

Haematological and systemic causes

• Serious: disseminated intravascular coagulation (abruption, retained dead foetus, amniotic fluid embolism, sepsis, pre eclampsia).
• HELLP syndrome and acute fatty liver of pregnancy.
• Thrombocytopenia (gestational, immune, thrombotic microangiopathy), von Willebrand disease and other inherited bleeding disorders.
• Anticoagulant therapy, antiplatelet therapy.
• Malaria and viral haemorrhagic fevers in endemic regions.

Non genital bleeding mistaken for vaginal bleeding

• Haemorrhoids and rectal bleeding.
• Haematuria from urinary tract infection or stones.
• Heavy discharge, loss of liquor or mucous plug.

Stepwise reasoning

1. Resuscitate first. Treat the mother, then the foetus.
2. Establish the foetal heart status and gestation, and apply continuous cardiotocography from viability.
3. Check the placental site on the most recent scan and, if unknown, perform an ultrasound before any vaginal examination.
4. Send blood tests early, including fibrinogen, because the early fall in fibrinogen predicts severe haemorrhage in abruption.
5. Decide on delivery by maternal condition, foetal condition, gestation and diagnosis.

First line tests

• Full blood count (the haemoglobin lags behind loss), group and save; crossmatch 4 units for major or massive bleeding, abruption or praevia with active bleeding.
• Coagulation screen with Clauss fibrinogen (under 2 g/L predicts severe haemorrhage; in pregnancy a value under 3 g/L is already low), prothrombin time and activated partial thromboplastin time, platelets.
• Urea, creatinine, electrolytes, liver function tests, uric acid and lactate dehydrogenase (pre eclampsia, HELLP), lactate and blood gas.
• Maternal rhesus status and antibody screen.
• Kleihauer or flow cytometry (foetomaternal haemorrhage) in all rhesus negative women, and in any woman with trauma or a sinusoidal cardiotocography.
• Urine dipstick for protein, culture if symptoms.
• Cardiotocography: normal baseline 110 to 160 beats/min, variability 5 to 25 beats/min, no decelerations; a sinusoidal pattern, bradycardia or repeated late decelerations indicate foetal hypoxia or anaemia.

Ultrasound

• Transabdominal ultrasound to locate the placenta, foetal presentation, liquor volume and cardiac activity. Transvaginal ultrasound is safe for placental localisation when the probe is placed carefully, and is more accurate than transabdominal ultrasound for low placentas.
• Placenta praevia: the placenta covers the internal os. A low lying placenta has its edge 20 mm or less from the os. Women with praevia on a scan at 20 weeks need a repeat scan at 32 weeks, because most low placentas move up as the lower segment forms.
• Placenta accreta spectrum: loss of the retroplacental clear zone, thinning of the myometrium, lacunae, bladder wall interruption, bridging vessels on colour Doppler; MRI helps for posterior placentas and suspected parametrial invasion.
• Abruption: ultrasound is insensitive (a normal scan does not exclude it). Retroplacental clot, a thickened placenta and a subchorionic collection support the diagnosis.
• Vasa praevia: transvaginal colour Doppler over the os showing vessels with foetal heart rate pulsation.
• Foetal growth, liquor and umbilical artery Doppler once stable.

Targeted tests

• Blood cultures, vaginal swabs and nucleic acid amplification tests if infection is suspected.
• Thromboelastography where available, to guide products.
• Toxicology screen if cocaine use is suspected.
• MRI pelvis for accreta spectrum.
• Alkali denaturation test (Apt test) for foetal blood in a sample of vaginal blood, when vasa praevia is possible and time allows.

Limitations. Visible blood loss does not reflect true loss. Ultrasound misses most abruptions. Fibrinogen can be normal early and fall rapidly. A normal cardiotocography does not exclude abruption, which can deteriorate in minutes. Haemoglobin and haematocrit lag behind loss.

Immediate steps.

• Call for senior obstetric, anaesthetic, midwifery and neonatal help for any major or massive loss, or any instability.
• Position the woman in the left lateral tilt (15 degrees) or with manual uterine displacement.
• Give oxygen 10 to 15 L/min by mask with a reservoir bag if shocked.
• Insert two large bore (14 or 16 gauge) cannulae, take blood for the first line tests, and send for cross match.
• Give warmed crystalloid (sodium chloride 0.9% or Hartmann solution) up to 2 L in 500 mL aliquots, then blood early rather than more crystalloid.
• Use group specific or O negative blood if the bleeding is torrential and the cross matched blood is not ready (red cell units that are K negative for women of childbearing age).
• Activate the major haemorrhage process. Keep nil by mouth.

Tranexamic acid. Give tranexamic acid 1 g intravenously over 10 minutes at the start of treatment, and repeat 1 g once if bleeding continues after 30 minutes. The evidence for benefit in antepartum bleeding is extrapolated from postpartum haemorrhage. A single emergency dose is not reduced for renal impairment; reduce repeat doses when the creatinine is raised. It is contraindicated with active thromboembolic disease or disseminated intravascular coagulation in which thrombosis predominates, except by specialist decision.

Blood products and coagulopathy

• Packed red cells to keep haemoglobin over 80 g/L in ongoing bleeding (over 70 g/L is adequate in a stable woman).
• Fibrinogen: give fibrinogen concentrate 2 to 4 g intravenously or cryoprecipitate (two pools, about 10 units) if the Clauss fibrinogen is under 2 g/L, or earlier in abruption with ongoing bleeding. Repeat to keep fibrinogen over 2 g/L.
• Fresh frozen plasma 12 to 15 mL/kg when the prothrombin time or activated partial thromboplastin time ratio exceeds 1.5, or empirically after 4 units of red cells in massive bleeding.
• Platelets to keep a count over 50 x 10^9/L in active bleeding, and over 75 x 10^9/L when surgery is expected (one adult dose).
• Calcium gluconate 10% 10 mL (1 g) intravenously over 10 minutes after 4 or more units of blood or if ionised calcium is under 1.1 mmol/L.
• Avoid hypothermia: warm all fluids.

Placental abruption

• Resuscitate and monitor the foetus continuously.
• Live foetus with a gestation of viability and compromise (abnormal cardiotocography), or a maternal condition that is worsening: emergency caesarean section, category 1, with the aim of birth within 30 minutes of decision.
• Live foetus, stable mother and a normal cardiotocography at less than 34 weeks: expectant management in hospital with continuous monitoring, and corticosteroids if delivery is likely.
• Foetal death: vaginal birth is the aim if the mother is stable, with amniotomy and oxytocin. Correct coagulopathy before and during birth. Caesarean section for maternal instability or failure to progress.
• Maintain urine output at 0.5 mL/kg/h or more (renal failure and acute tubular necrosis follow severe loss).
• Expect uterine atony after birth (Couvelaire uterus).

Placenta praevia

• Admit women with bleeding. Cross match 2 to 4 units. Give anti D immunoglobulin to rhesus negative women.
• Corticosteroids: betamethasone 12 mg intramuscularly, two doses 24 hours apart, or dexamethasone 6 mg intramuscularly every 12 hours for four doses, between 24 weeks and 34 weeks and 6 days (consider up to 36 weeks and 6 days on specialist advice), when delivery is expected within 7 days.
• Magnesium sulphate for foetal neuroprotection when delivery is imminent before 30 weeks: 4 g intravenously over 15 to 30 minutes, then 1 g/h until birth or for a maximum of 24 hours. Monitor reflexes, respiratory rate and urine output, and reduce the dose in renal impairment.
• Elective caesarean section at 36 weeks to 37 weeks and 6 days in women without bleeding, earlier (34 to 36 weeks and 6 days) if there has been bleeding. Consultant obstetrician and anaesthetist present. Do not place a woman with a major praevia and active bleeding in labour.
• Tocolysis is not given to women with praevia and bleeding.

Placenta accreta spectrum. Plan birth at 35 to 36 weeks and 6 days in a centre with blood bank, interventional radiology, urology and surgery, and intensive care. Options include caesarean hysterectomy, conservative management with the placenta left in place, and balloon occlusion.

Consent for hysterectomy. Cell salvage, tranexamic acid 1 g intravenously at induction, and oxytocin.

Vasa praevia. Elective caesarean section at 34 to 36 weeks (admit from 30 to 34 weeks, adjusted to risk and distance from hospital). Emergency caesarean section, category 1, if the membranes rupture with bleeding or foetal heart abnormality. Neonatal team ready for transfusion.

Uterine rupture. Resuscitate, laparotomy, repair or hysterectomy, neonatal resuscitation, and blood.

Postpartum haemorrhage prevention and treatment after antepartum haemorrhage.

• Active management of the third stage.
• Oxytocin 5 units slowly intravenously or 10 units intramuscularly, then an infusion of 40 units in 500 mL sodium chloride 0.9% at 125 mL/h (10 units/h) for 4 hours.
• Ergometrine 500 microgram intramuscularly or slowly intravenously (contraindicated in hypertension, pre eclampsia, cardiac disease).
• Carboprost 250 microgram intramuscularly every 15 minutes, maximum 8 doses (contraindicated in asthma).
• Misoprostol 800 microgram sublingually or 1000 microgram rectally.
• As the haemorrhage continues: bimanual compression, intrauterine balloon tamponade, uterine compression sutures, uterine artery embolisation, internal iliac ligation and hysterectomy.
• Repeat tranexamic acid 1 g intravenously if bleeding continues.

Rhesus immunoglobulin. Give anti D immunoglobulin to all rhesus negative women with antepartum haemorrhage within 72 hours: at least 500 IU intramuscularly from 20 weeks (250 IU before 20 weeks). Use a Kleihauer or flow cytometry test to calculate an additional 125 IU for each 1 mL of foetal red cells over 4 mL. A single 1500 IU (300 microgram) dose is used in some services and covers a larger foetomaternal haemorrhage.

Minor bleeding with praevia excluded. Observe for at least 24 hours if bleeding is more than spotting. Do cardiotocography, ultrasound for growth and liquor, and a speculum examination. Offer discharge once bleeding has stopped, the foetus is well and the woman lives close to the hospital.

Cervical causes. Cervical polyps and ectropion rarely need treatment. Refer suspected carcinoma for colposcopy and biopsy. Treat infection: metronidazole 400 mg orally twice daily for 5 to 7 days for trichomoniasis and bacterial vaginosis; ceftriaxone 1 g intramuscularly once for gonorrhoea; azithromycin 1 g orally once for chlamydia in pregnancy.

Trauma. Resuscitate the mother. Cardiotocography for at least 4 hours after minor trauma, and up to 24 hours if there are contractions, bleeding, tenderness or abnormal tracing. Kleihauer for rhesus negative women, and screen for abuse.

Neonatal planning. Inform the neonatal team early. Delivery before 34 weeks needs a neonatal unit with intensive care. Arrange in utero transfer when not available.

Special groups.

• Women who decline blood: manage in a centre with cell salvage, tranexamic acid, intravenous iron, erythropoietin and early surgical control.
• Women with HIV: continue antiretroviral therapy.
• Women with inherited bleeding disorders: haematology and replacement of factor (von Willebrand factor concentrate).

Monitoring. Pulse, blood pressure and respiratory rate every 15 minutes while unstable, urine output hourly, fibrinogen and haemoglobin every 1 to 2 hours in active bleeding, continuous cardiotocography, and thromboelastography where available. After stabilisation, monitor for at least 24 hours and then routine observations.

Referral and escalation. Call the consultant obstetrician, anaesthetist, haematologist, blood bank and neonatal team immediately for major or massive loss. Refer to a unit with intensive care for accreta spectrum, unstable bleeding or severe coagulopathy. Refer to interventional radiology for embolisation.

Admission criteria. All women with major or massive bleeding, abruption, praevia with bleeding, abnormal cardiotocography, pain, reduced foetal movements, pre eclampsia, or any bleeding more than spotting. Women with minor bleeding may go home after 24 hours of observation if the foetal state is normal, the cause is a cervical lesion or the bleeding was confined to a show, and transport is quick.

Discharge and follow up. Written instructions; antenatal review within 1 week; growth scans every 2 to 4 weeks after abruption or unexplained bleeding; planned delivery. Anti D if indicated. Thromboprophylaxis with enoxaparin after delivery as risk dictates.

Safety netting. Return at once for any further bleeding, abdominal pain, tightening of the abdomen, reduced foetal movements, leakage of fluid, dizziness or fainting. Women with a known praevia should not have intercourse and should attend a hospital with a theatre.