Antepartum haemorrhage

What is an antepartum haemorrhage?

Antepartum haemorrhage (APH) is usually defined as bleeding from the birth canal after the 24th week of pregnancy.¹ It can occur at any time until the second stage of labour is complete; bleeding following the birth of the baby is postpartum haemorrhage.

Bleeding before 24 completed weeks of pregnancy is miscarriage, which is discussed in the separate Miscarriage article.

How common is an antepartum haemorrhage? (Epidemiology)

In the UK and Ireland there were 18 women who died from obstetric haemorrhage during or up to six weeks after the end of pregnancy in 2019-21, 10 of which were due to antepartum haemorrhage. This represents an overall mortality rate of 0.82 per 100,000 maternities (95% CI 0.48-1.32) and accounts for 7% of all maternal deaths in this time frame.

When looking at specific causes of death from APH, two deaths were caused by placenta praevia and four each were caused by placental abruption and placenta accreta.

Worldwide, obstetric haemorrhage is responsible for 27% of all maternal deaths, most of which occur in low- and middle-income countries.²

APH affects 3-5% of all pregnancies.¹

Up to 20% of very preterm babies are born in association with APH, which explains the association between APH and cerebral palsy.

Antepartum haemorrhage causes (aetiology)¹

No definite cause is diagnosed in about 50% of all women who present with antepartum haemorrhage; however, placenta praevia and placental abruption are the major identifiable causes:

• Placenta praevia: insertion of the placenta, partially or fully, in the lower segment of the uterus. See the separate Placenta praevia article. A 2017 study found a total of 29 articles were included. The pooled overall prevalence of APH among pregnant women with placenta previa was 51.6%

• Placental abruption: premature separation of a normally placed placenta. See the separate Placenta problems (Placenta accreta and placental abruption) article.

• Local causes - eg, vulval or cervical infection, trauma or tumours.

• Partner violence is common in pregnancy, with reported prevalence of between 2% and 35%, however it is often unreported and so the actual prevalence may be higher. It may result in APH. Women should be asked about this, particularly if there are repeated episodes. See the separate Domestic violence article. ³

• Vasa praevia: bleeding from fetal vessels in the fetal membranes, leading to high risk of fetal haemorrhage and death at rupture of the membranes. See the separate Placenta problems (Placenta accreta and placental abruption) article

• Uterine rupture: rare but very dangerous for both mother and baby. See the separate Uterine rupture article.

• Inherited bleeding problems are rare. Whilst up to 1 in 1000 pregnancy women may have von Willebrand disease, it is clinically significant for only 10% of this number. Other bleeding conditions are less common, with a prevalence of under 1 in 100,000. ⁴

• Whilst risk factors for APH, in particular for placenta praevia and placental abruption, have been identified, APH cannot be predicted; 70% of cases of placental abruption occur in low-risk pregnancies.

• There is limited evidence that APH can be prevented but women should be encouraged to change modifiable risk factors such as smoking and cocaine and amfetamine abuse. ¹

• Antenatal anaemia should be investigated and treated. Iron-deficiency anaemia reduces a woman's tolerance to bleeding. It has also been suggested that severe anaemia may impair uterine oxygenation and make uterine atony more likely.⁵

Antepartum haemorrhage symptoms

• Bleeding, which may be accompanied by pain (suggestive of placental abruption) or be painless (suggesting placenta praevia).

• Uterine contractions may be provoked.

• There may be malpresentation or failure of the fetal head to engage, with placenta praevia.

• There may be associated signs of fetal distress.

• If the bleeding is severe, the mother may show signs of hypovolaemic shock; however, young, fit, pregnant women can compensate very well until sudden and catastrophic decompensation occurs.

Antepartum haemorrhage treatment and management¹

Always admit the patient to hospital for assessment and management, even if bleeding is only a very small amount; there may be a large amount of concealed bleeding with only a small amount of revealed vaginal bleeding. Phone 999/112/911 if there are any major concerns regarding maternal or fetal well-being.

• Estimate amount of blood loss. This is often underestimated and needs to combined with an assessment of signs of clinical shock:

  • Minor haemorrhage = blood loss <50 ml and has stopped.

  • Major haemorrhage = blood loss 50-1000 ml with no signs of shock.

  • Massive haemorrhage = blood loss >1000 ml and/or signs of shock.

• The mainstays of management of massive haemorrhage are effective communication between clinical staff, resuscitation, monitoring and accurate diagnosis of the underlying cause. The bleeding will be arrested by delivery of the fetus.

• Severe bleeding: the mother's life should take priority. Any decision regarding the delivery of the baby should wait until the mother's condition is stable.

• Fetal distress: urgent delivery of the baby, irrespective of gestational age. Fetal compromise is an important indicator of reduced circulating blood volume.

• No vaginal examination should be attempted, at least until a placenta praevia is excluded by ultrasound. It may initiate torrential bleeding from a placenta praevia.

• Resuscitation can be inadequate because of underestimation of blood loss and misleading maternal response, especially in small women. Medical response should be considered as a proportion of blood volume, based on body weight. ⁶

• Blood tests:

  • FBC and 'group and save'. NB: initial Hb may not reflect degree of blood loss. Low platelet count may suggest significant abruption.

  • Clotting studies, if platelet count is abnormal, as coagulopathy is common and should be anticipated.

  • Crossmatch four units and check U&Es and LFTs, if there is major or massive haemorrhage.

• Gentle palpation of the abdomen to determine the gestational age of the fetus, presentation and position.

• Fetal monitoring.

• Arrange urgent ultrasound to exclude placenta praevia; ultrasound cannot exclude placental abruption, which is a clinical diagnosis.

• With every episode of bleeding, a rhesus-negative woman should have a Kleihauer test and be given prophylactic anti-D immunoglobulin.⁷

• Maternal corticosteroids should be offered to any woman at risk of preterm birth, who is between 24⁺⁰ and 33⁺⁶ weeks of gestation.⁸

Further management

• Further management will depend on fetal distress, the cause of the APH, the extent of bleeding and gestation.

• All women need to be assessed individually, taking into account not only the amount of blood loss but also any relevant current or past medical and obstetric history.

• Placenta praevia: see the separate Placenta praevia article.

• Moderate or severe placental abruption: see the separate Placenta problems (Placenta accreta and placental abruption) article.

Complications of an antepartum haemorrhage

• Premature labour.

• Disseminated intravascular coagulopathy.

• Acute kidney injury.

• Postpartum haemorrhage.

• Placenta accreta: this may complicate cases of placenta praevia but is rare in the absence of placenta praevia or previous caesarean section. See the separate Placenta problems (Placenta accreta and placental abruption) article.

• Anaemia.

• Infection.

• Prolonged hospital stay.

• Psychological sequelae.

• Fetal complications:

  • Fetal hypoxia.

  • Fetal growth restriction.

  • Prematurity, both iatrogenic and spontaneous.

  • Fetal death.

Prognosis

• Maternal mortality is lower if managed by an experienced obstetrician and if no vaginal examination is performed before admission to hospital.

• According to a 2017 systematic review of 123 studies, abruption is the most frequently reported risk factor for stillbirth (range: 3.4-51.8%), neonatal death (range: 1.1-19%), and overall perinatal mortality (range: 4-56.3%).⁹ However, more than half (55%) of excess perinatal deaths associated with abruption are attributed to preterm birth.

• In pregnancies when the cause of APH is not known, there is still a greater risk of preterm delivery and induced labour but no increase in perinatal mortality after adjusting for gestational age.¹⁰