Antepartum haemorrhage (APH) is defined as any bleeding from the genital tract after the 20th week of pregnancy and before the onset of labour.

Some causes of antepartum haemorrhage might also cause intrapartum bleeding, such as an abruption or placenta praevia. There are four principal causes:

  • Placenta Praevia
  • Placental abruption
  • Vasa Praevia
  • Cervical and lower genital tract bleeding

Bleeding can range from mild to massive where it constitutes a medical emergency.

Classification of APH

APH is classically divided into 4 principle groups:

1. Placenta Praevia
  • Around 30% of APH cases
  • Bleeding from the placenta when it is inserted wholly or partly into the lower segment of the uterus in the third trimester of pregnancy
  • As the placenta occupies the lower uterine segment, the presenting part may be high or the fetus may be mal-presented due to restricted decent into the pelvis

2. Placental abruption

  • Around 25% of APH cases
  • Premature separation of a normally situated placenta from the uterine wall that occurs before delivery of the foetus

3. Vasa Praevia

  • A rare condition
  • Umbilical blood vessels traverse the fetal membranes of the lower uterine segment above the cervix, unsupported by the umbilical cord or the placenta
  • Bleeding from these vessels is almost always associated with rupture of membranes

4. Cervical and lower genital tract bleeding

  • Around 45% of APH cases
  • Bleeding from the cervix or vagina.


Placenta Praevia

It is defined as the implantation of the placenta over or near the internal os of the cervix.

Bleeding is more likely to occur in the third trimester when the lower uterine segment is developing or during contractions with cervical dilatation, which is thought to cause shearing forces, leading to disruption of the placental attachment.

From the second trimester, a placenta praevia may be also associated with vasa praevia (see below).


  • Minor placenta praevia: placenta not lying over the cervical os but encroaching on the lower uterine segment.
  • Major placenta praevia: placenta lying over the cervical os.

Additionally placenta praevia can be classified according to the degree of placental adherence to the uterus:

  • Placenta accreta (superficial)
  • Placenta increta (into muscle)
  • Placenta percreta (through muscle)


  • A low-lying placenta occurs in 5% of pregnancies at 16 – 18 weeks gestation but only 0.5% pregnancies at term.
  • The change of placental position results from the formation of the lower uterine segment and which moves the placenta upwards with the expanding uterus.

Risk factors

  • Previous caesarean section, the risk increases in prevalence with each caesarean section.


  1. Haemorrhage
  2. Fetal effects:
    • Intrauterine growth restriction (IUGR), due to abnormal placental implantation and vascularisation in the area of the uterus destined to be the lower segment
    • A higher incidence of premature pre-labour rupture of the membranes PPROM) due to blood affecting the integrity of the membranes
Placental abruption

Abruption is an antepartum haemorrhage due to the premature separation of a normally situated placenta from the myometrial wall that occurs before delivery of the fetus.

The exact aetiology is unknown, but the final pathophysiology is likely rupture of a spiral artery with haemorrhage into the decidua basalis leading to separation of the placenta. The small vessel disease seen in abruptio placentae may also result in placental infarction.

Placental abruption is associated with a high maternal and neonatal morbidity and mortality.


Placental abruption can be classified in a number of ways:

  1. Revealed verses concealed
    • Revealed:
      • Blood escapes through the vagina.
      • Note that when there is revealed bleeding it is also likely that there is a significant concealed proportion of bleeding as well
    • Concealed:
      • Bleeding occurs behind the placenta, with no evidence of bleeding from the vagina.
  2. Degree of separation:
    • The increasing degree of abruption will correlate with increasing signs of maternal and fetal compromise and biochemical abnormalities.
  3. Position of the abruption:
    • Marginal placental abruption: most common by far
    • Retro-placental abruption 
    • Pre-placental abruption

Risk factors

  1. Trauma, this is a major risk factor
    • A woman involved in trauma, such as an MVA, should be evaluated for abruption.
    • An abruption may occur in the absence of direct abdominal trauma or, an abruption may become apparent several hours or days after the trauma.
  2. Chronic hypertension
  3. Preeclampsia
  4. Thromobphilia
  5. Previous placental abruption
  6. Smoking
  7. Drug abuse: in particular cocaine abuse.
  8. Chorioamnionitis
  9. Sudden reduction in size of an over-distended uterus:
    • Rupture of membranes in association with polyhydramnios
    • Between births of multiple pregnancies


  1. Maternal shock
  2. Fetal distress and death
  3. Coagulopathies, in particular DIC, is a major complication in abruptions
  4. Renal failure (shock and microthrombosis)
  5. Postpartum haemorrhage, may occur as a consequence of both a bleeding disorder     (thrombocytopenia / DIC) and uterine atony.
Vasa Praevia

Vasa praevia is a condition in which the umbilical vessels, unsupported by either the umbilical cord or placental tissue, traverse the fetal membranes of the lower segment above the cervix.


  • Type I
    • Around 90% of cases with vasa previa
    • Abnormal fetal vessels connect a velamentous cord insertion with the main body of the placenta
  • Type II
    • Around 10% of cases with vasa previa
    • Abnormal vessels connect portions of a bilobed placenta.
    • Placenta with a succenturiate lobe.

Due to this association, vasa previa needs to be excluded in patients with variant placental morphology

Risk factors:

  1. Placenta praevia
  2. Low lying placenta
  3. Bilobate placenta
  4. Succenturiate placenta


Bleeding may result from the rupture of these vessels usually during rupture of the membranes.

Cervical and lower genital tract bleeding


  • Cervical ectropion
  • Carcinoma
  • Cervicitis/ infection
  • Polyps
  • Vulval varices
  • Trauma

Clinical features

Placenta Praevia

Women with a placenta praevia generally present in one of the following ways:

  • With an antepartum haemorrhage.
  • As a finding on ultrasound in an asymptomatic woman.
  • With a fetal malpresentation or a high mobile presenting part in late pregnancy.
  • With vaginal bleeding in labour

The clinical features of an APH due to placenta previa include:

  1. Painless bleeding:
    • Bleeding can also be provoked by a digital examination or by intercourse.
    • Vaginal examination should be done with a speculum only, to assess the site of bleeding.
  2. Bleeding can be recurrent (and often progressively worse):
    • The most common pregnancy complication arising from a placenta praevia is intermittent vaginal bleeding
    • Intermittent bleeding may lead to maternal anaemia, monitor for and maintain adequate maternal haemoglobin levels and iron stores
  3. Blood loss is largely “revealed
  4. Blood tends to be “bright”
  5. Usually no abdominal tenderness
  6. Presenting part is high and mobile
Placental abruption

The clinical features of an APH due to placental abruption include:

  1. Painful bleeding:
    • This contrasts to the painless bleeding in placenta praevia or bleeding from the cervix or lower genital tract
    • Abruption should be high on the differential diagnosis list whenever abdominal pain occurs in the second half of pregnancy.
  2. Blood tends to be “dark”
  3. Abdominal / back tenderness:
    • Where the abruption is substantive, the uterus may be tender on palpation or may feel hard or tense.
  4. Blood loss may be largely “concealed”.
    • The absence of vaginal bleeding therefore does not rule out an abruption.
    • Note that when there is revealed vaginal bleeding it is also likely that there is a significant concealed proportion of bleeding as well.
  5. Fundus may be higher than expected for dates
  6. Uterine activity:
    • Uterine contractions are a common finding with placental abruption.
    • This is a sensitive marker of abruption and, in the absence of vaginal bleeding, should raise the suggestion of an abruption, especially following some form of trauma or in a patient with multiple risk factors.
    • Symptoms, signs and clinical examination findings of preterm labour may also coexist with abruption.
  7. Fetal demise:
    • In some cases, fetal demise may be the only indication that an abruption has occurred.
Vasa Praevia

Vasa praevia will only rarely present as an antepartum haemorrhage. Detection is more likely:

  • On vaginal examination with palpation of fetal vessel
  • Vaginal bleeding at amniotomy
  • Sudden severe abnormalities of the fetal heart rate in labour.
Cervical and lower genital tract bleeding

In these cases, bleeding is usually revealed and painless.

Cervical ectropion / dysplasia:

  • Bleeding from the surface of the cervix caused by contact with the speculum may indicate cervical pathology and warrant further investigation i.e. pap smear/colposcopy.


  • Bleeding from the walls of the vagina may indicate a severe vaginitis.

Genital Tract Polyps:

  • Cervical polyps are usually apparent upon speculum examination.

Vulval or vaginal varices:

  • These will be apparent upon speculum examination.


  • Consider victims of domestic violence and sexual assault.

Bleeding associated with the onset of labour (i.e “show”) is not traditionally considered an Antepartum Haemorrhage.

If the cervix is effaced or a dilated cervix and other causes of bleeding are excluded, the bleed is likely to be a “show”.


  1. Blood tests:
    • FBE
    • U&Es/ glucose
    • Coagulation profile
    • Thrombophilia screen: women who have had a placental abruption should be screened for both congenital and acquired thrombophilias.
    • Blood group and cross match as clinically indicated
    • Kleihauer test
  2. CTG Monitoring:
    • All cases (24 weeks and beyond) should have CTG monitoring to assess fetal well being and maternal contractions.
  3. Ultrasound:
    An ED US scan can be done as an initial screen for fetal movements and detection of the fetal heart rate.
    • Placenta praevia:
      • Trans-vaginal or trans-labial ultrasound is now the preferred method for           localization of a low-lying placenta.
      • Sonography and it is safe to perform, even in the presence of bleeding.
      • It is easier to identify an anterior than a posteriorly located placenta praevia. This is because the fetus often obscures the leading edge of a posterior placenta.
    • Placental abruption:
      • Placental abruption may be appreciated on US, but it is not the ideal investigation to diagnose it.
      • Unless there is substantive placental separation, (which in any case will be clinically apparent), a placental abruption is not likely to be seen on ultrasound.
    • Vasa Praevia:
      • The diagnosis is often made with trans-abdominal Doppler sonography demonstrating flow within vessels that are seen overlying the internal cervical os.
    • Uterine Rupture:
      Reported sonographic signs of uterine rupture include: 3
      • The identification of the protruding portion of the amniotic sac
      • An endometrial or myometrial defect
      • An extra-uterine haematoma
      • Haemoperitoneum or free fluid
  4. MRI
    • MRI is the gold standard to imaging the placenta and its relationship to the cervix, although in most instances it is not required.
    • MR imaging can accurately detect placental abruption and should be considered after negative US findings. 3
    • Haemorrhage due to abruption appears as an area of medium to high signal intensity on T1 and high signal intensity on T2 weighted image, located between the placenta and uterine wall.
    • Multiplanar MR imaging offers a comprehensive assessment of the uterine wall and the peritoneal cavity when uterine rupture is suspected.


  1. Attend to any immediate ABC issues of resuscitation:
    • IV access: one or two size 16 gauge or larger bore cannulae
    • Initial crystalloid fluid resuscitation as required
  2. Give blood and blood products as indicated:
    • Packed RBCs
    • FFP
    • Platelets
    • Cryoprecipitate
    • For severe/life-threatening bleeding, O-negative blood and activation of a massive transfusion protocol will be required.
  3.  Analgesia:
    Note that the need for analgesia should raise suspicion of:
    • A moderate or severe placental abruption, and/or
    • That the woman is in labour.
  4. Insertion of an indwelling catheter
  5. Establish CTG monitoring
  6. Anti D Immunoglobulin:
    • If the woman is Rhesus negative
    • Give an initial dose of 625 IU IM
    • The Kleihauer test is then used to estimate the exact degree of feto-maternal haemorrhage and thus the requirement for any additional dosing of Anti-D immunoglobulin.
  7. Steroids:
    • Corticosteroids are given if the gestation is less than 34 weeks.
    • Give two doses of betamethasone 11.4mg, 24 hours apart, if delivery is not planned within the next 12 hours.
  8. MgSO4:
    • The treating obstetrician may consider MgSO4 for fetal neuroprotection if the gestation is < 30 weeks and imminent delivery is likely.
  9. Obstetric Management:
    The subsequent mode and urgency of delivery will then depend on several factors including:
    • The risk to the mother:
      • Degree of shock/ coagulopathy.
    • Co-existent conditions (e.g. preeclampsia).The risk to the fetus:
      • Gestational age
      • Cardiotocography findings
    • The exact cause.

The timing of birth must weigh the risks of the maternal condition and prematurity, against those of continuing the pregnancy.

PV examination is contraindicated in APH, (as it may promote significant bleeding in cases of placenta previa).


All patients with APH must be referred urgently to an Obstetric Unit.

All cases will require admission.

In cases of severe hemorrhage, the following will also require early referral:

  • Anaesthetics
  • Paediatrics
  • If blood component therapy is indicated, advice should also be sought from a haematologist regarding the most appropriate therapy.



  • Antepartum Haemorrhage Green-top Guideline No. 63
  • Giordano R, Cacciatore A, Cignini P, Vigna R, Romano M. Antepartum haemorrhage. J Prenat Med. 2010 Jan;4(1):12-6. 
  • Radswiki T, Kogan J, Glick Y, et al. Placental abruption. Reference article, Radiopaedia.org
  • Crafter H, J B. Common problems associated with early and advanced pregnancy. In: Marshall J,
  • Raynor M, editors. Myles textbook for midwives. 16th ed. Edinburgh: Churchill Livingstone Elsevier; p. 221-42.

Fellowship Notes

Dr Jessica Hiller LITFL Author

Doctor at Sir Charles Gairdner Hospital in Western Australia. Graduated from Curtin University in 2023 with a Bachelor of Medicine, Bachelor of Surgery. I am passionate about Obstetrics and Gynaecology, with a special interest in rural health care.

Physician in training. German translator and lover of medical history.

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