Antepartum Haemorrhage
Antepartum haemorrhage (APH) is vaginal bleeding from 24 weeks gestation until delivery, complicating 3-5% of pregnancies and requiring urgent assessment for maternal and fetal wellbeing.
Key Facts
APH is defined as vaginal bleeding from 24+0 weeks gestation until delivery Complicates 3-5% of pregnancies; most common causes are placenta praevia and placental abruption RCOG classification: minor (<50 mL), major (50-1000 mL), massive (>1000 mL or signs of shock) Never perform digital vaginal examination until placenta praevia has been excluded by ultrasound Anti-D immunoglobulin must be given to all RhD-negative women with APH (minimum 500 IU, Kleihauer test to guide dosing) Unexplained APH accounts for approximately 50% of cases Antenatal corticosteroids should be given if <34+6 weeks and delivery anticipated within 7 days APH is associated with increased risk of preterm delivery, FGR, and perinatal mortality
Overview
Key Facts
Antepartum haemorrhage is any bleeding from the genital tract from 24+0 weeks of pregnancy until delivery. It is a common obstetric emergency requiring systematic assessment to determine the cause, severity, and appropriate management.
Epidemiology
- Complicates 3-5% of pregnancies
- Accounts for significant proportion of obstetric emergencies
- Placenta praevia: 0.5% of pregnancies at term
- Placental abruption: 1% of pregnancies
- Unexplained APH: approximately 50% of cases
Aetiology
- Placenta praevia (low-lying placenta covering or near the cervical os)
- Placental abruption (premature separation of normally sited placenta)
- Vasa praevia (fetal vessels crossing the cervical os - rare but high fetal mortality)
- Marginal bleeding (bleeding from placental edge)
- Cervical causes: cervical ectropion, cervical cancer, cervical polyp
- Infection: cervicitis, vaginitis
- Unexplained (most common overall)
Pathophysiology
- Placenta praevia: placental implantation in lower uterine segment; bleeding occurs as lower segment develops
- Abruption: premature separation due to haemorrhage into the decidua basalis; may be concealed or revealed
- Vasa praevia: rupture of unprotected fetal vessels, typically at membrane rupture
Clinical Presentation
Placenta Praevia Presentation
- Painless bright red vaginal bleeding (classically recurrent)
- Soft, non-tender uterus
- Malpresentation common (breech, transverse lie)
- Usually no fetal compromise unless massive bleeding
Placental Abruption Presentation
- Constant abdominal pain with or without vaginal bleeding
- Woody hard, tender uterus on palpation
- Degree of shock may be disproportionate to visible blood loss (concealed haemorrhage)
- Fetal distress or intrauterine fetal death
Vasa Praevia Presentation
- Painless vaginal bleeding at membrane rupture
- Rapid fetal compromise (sinusoidal CTG pattern)
- Fetal mortality >50% if not diagnosed antenatally
Red Flags
- Haemodynamic instability (tachycardia, hypotension)
- Woody hard uterus (abruption)
- Abnormal CTG
- Bleeding at membrane rupture (vasa praevia)
- Large volume blood loss (>500 mL)
- Coagulopathy
Differential Diagnosis
| Diagnosis | Key Features | Investigation |
|---|---|---|
| Placenta praevia | Painless bright red bleeding, soft uterus | Ultrasound (TVS) |
| Placental abruption | Painful, tense woody uterus, shock | Clinical diagnosis, USS may be normal |
| Vasa praevia | Bleeding at membrane rupture, fetal distress | Antenatal USS with colour Doppler |
| Cervical ectropion | Postcoital bleeding, visualised on speculum | Speculum examination |
| Cervical cancer | Irregular bleeding, visible lesion | Speculum, cervical biopsy |
| Bloody show | Small amount of blood-stained mucus, term | Clinical assessment |
| Uterine rupture | Severe pain, previous CS scar, shock | Clinical, laparotomy |
Diagnosis / Investigation
Bedside
- ABCDE assessment and haemodynamic monitoring
- CTG (continuous fetal monitoring)
- Speculum examination (DO NOT perform digital VE until praevia excluded)
- Weigh pads/estimate blood loss
- Group and save / crossmatch urgently
Bloods
- FBC (haemoglobin, platelet count)
- Coagulation screen (PT, APTT, fibrinogen)
- Group and crossmatch (minimum 4 units in massive haemorrhage)
- Kleihauer test (all RhD-negative women - quantifies fetomaternal haemorrhage)
- U&Es, LFTs
Imaging
- Transabdominal ultrasound: placental localisation, fetal assessment
- Transvaginal ultrasound: gold standard for placental localisation (safe even with praevia)
- Doppler assessment of fetal wellbeing
Special Tests
- Apt test or haemoglobin electrophoresis if suspecting fetal blood (vasa praevia)
- Fibronectin or cervical length if preterm labour suspected
Management
Non-pharmacological
- ABCDE approach with simultaneous resuscitation
- Two large-bore IV cannulae (14-16G)
- Activate massive obstetric haemorrhage protocol if appropriate
- Senior obstetric and anaesthetic involvement
- Neonatal team alert
Pharmacological
- Anti-D immunoglobulin: 500 IU IM minimum to all RhD-negative women; Kleihauer to guide additional doses
- Antenatal corticosteroids: betamethasone 12mg IM × 2 (24h apart) if 24-34+6 weeks
- Tocolysis: may be considered if preterm labour with mild APH (nifedipine 20mg PO); contraindicated with significant abruption
- IV fluid resuscitation and blood product replacement as needed
- Tranexamic acid 1g IV in massive haemorrhage
Surgical/Interventional
- Placenta praevia: elective caesarean section at 36-37 weeks (RCOG GTG 27a)
- Major abruption: emergency delivery (usually caesarean section) if fetal compromise
- Vasa praevia: elective caesarean section at 34-36 weeks if diagnosed antenatally
- Uterine compression sutures (B-Lynch), balloon tamponade, or uterine artery embolisation for ongoing haemorrhage
Referral Criteria
- All APH requires hospital assessment
- Consultant obstetrician review for any significant APH
- Haematology input for coagulopathy
- Blood bank alert for massive haemorrhage
Prognosis
- Perinatal mortality varies by cause: placenta praevia (~1-2%), abruption (up to 30% in severe cases), vasa praevia (>50% if undiagnosed)
- Maternal mortality rare in developed countries but remains significant worldwide
- Recurrence risk: placenta praevia 4-8%, abruption 6-17%
- APH associated with increased risk of preterm delivery, FGR, and neonatal morbidity
- Women with unexplained APH have 2× risk of preterm delivery and 1.5× risk of low birth weight
Other Relevant Information
RCOG APH Severity Classification
| Category | Blood Loss | Management |
|---|---|---|
| Spotting | Staining only | Outpatient if stable |
| Minor | <50 mL | Admit, observe |
| Major | 50-1000 mL | Resuscitate, crossmatch |
| Massive | >1000 mL or shock | Major haemorrhage protocol |
Causes by Frequency
| Cause | Approximate Frequency |
|---|---|
| Unexplained | 50% |
| Placental abruption | 25-30% |
| Placenta praevia | 20% |
| Cervical causes | 5% |
| Vasa praevia | <1% |