Antepartum Haemorrhage

Introduction

Antepartum haemorrhage is bleeding from the genital tract from 24+0 weeks of gestation until the birth of the baby. The 24-week boundary is the legal threshold of fetal viability in the UK; bleeding before it is classified as a threatened miscarriage and managed through early pregnancy services rather than the labour ward.¹

It complicates 3-5% of pregnancies and is one of the more dangerous presentations in obstetrics, for three reasons. The volume seen per vaginam may bear no relationship to the volume lost, since a retroplacental clot can be entirely concealed. The physiological hypervolaemia of pregnancy allows a young woman to lose up to 1500 mL before her blood pressure falls, so the first sign of decompensation may be collapse. And there are two patients, one of whom depends on maternal circulating volume for oxygenation and will decompensate before the mother does.

This article covers the assessment and initial management of antepartum haemorrhage as a presentation. The individual causes are dealt with in their own articles, but the discriminating features are drawn together here because the immediate task at the bedside is to work out which one you are dealing with.

Causes

A bloody show, the passage of blood-stained mucus as the cervix effaces before labour, is physiological and should not be classified as an antepartum haemorrhage, but it is a diagnosis made only after significant causes have been excluded.

Grading blood loss

Assessment

Assessment and resuscitation happen simultaneously in significant bleeding. In a stable woman with minor bleeding, a structured history and examination come first.

History

• Volume and character of the bleeding, and whether it is continuing; ask about pads soaked, not just about the presence of blood
• Any precipitant: intercourse, trauma, a fall, road traffic collision, or domestic abuse - ask directly and in private
• Pain: abruption is painful and continuous, praevia is painless, labour pain is intermittent
• Rupture of membranes, particularly bleeding beginning at the moment the waters broke, which suggests vasa praevia
• Fetal movements
• The placental site on the 20-week anomaly scan, which is the single most useful piece of information in the notes
• Previous caesarean sections and uterine surgery, and any known placenta accreta spectrum
• Drug history including anticoagulants, and cocaine use, which causes abruption

Examination

• Full observations with a maternal early warning score; assess capillary refill and conscious level
• Abdominal palpation: a tense, tender, woody uterus indicates abruption; a soft, non-tender uterus points to praevia or a local cause
• Fetal lie and presentation - a high or malpresenting presenting part suggests praevia
• Symphysis-fundal height, which may be greater than expected if there is a concealed retroplacental clot
• Cardiotocography from 26 weeks, or auscultation of the fetal heart at lower gestations
• Speculum examination only once praevia has been excluded, to identify local causes and assess the os
• Digital vaginal examination only once praevia has been excluded

Investigations

A normal ultrasound never excludes abruption. Fresh retroplacental blood is isoechoic with placental tissue, so the scan is normal in the majority of clinically significant abruptions. Its role is to locate the placenta, assess the fetus and exclude praevia, not to rule out abruption.

Management

Immediate resuscitation in major or massive haemorrhage

• Call for help: senior obstetrician, anaesthetist, midwife coordinator, haematologist, blood bank and neonatal team; activate the major obstetric haemorrhage protocol
• ABCDE approach with high-flow oxygen and left lateral tilt or manual uterine displacement to relieve aortocaval compression
• Two large-bore cannulae, with bloods taken as they are sited
• Warmed crystalloid while awaiting blood, then red cells; use O negative if the need is immediate
• Early fresh frozen plasma, cryoprecipitate and platelets guided by results and by point-of-care testing where available; keep fibrinogen above 2 g/L
• Insert a urinary catheter and monitor hourly urine output
• Continuous cardiotocography once the mother is being resuscitated

Resuscitation of the mother is resuscitation of the fetus. A fetal bradycardia in the context of maternal haemorrhage will often recover once maternal circulating volume is restored, and rushing to theatre with an inadequately resuscitated and coagulopathic mother makes both outcomes worse.

Adjuncts

• Anti-D immunoglobulin for RhD negative women within 72 hours, with the dose determined by the Kleihauer result after 20 weeks; repeat at 6-weekly intervals if bleeding recurs
• Antenatal corticosteroids between 24+0 and 34+6 weeks where preterm birth is anticipated, and consider up to 35+6 weeks
• Magnesium sulfate for fetal neuroprotection if birth is expected within 24 hours before 30 weeks, and considered up to 34 weeks
• Tocolysis is contraindicated in antepartum haemorrhage with a compromised fetus or ongoing significant bleeding
• Thromboprophylaxis is reassessed once bleeding has settled - these women are at increased VTE risk from immobility and transfusion
• Tranexamic acid is established for postpartum haemorrhage; its role in antepartum haemorrhage is less well defined and is a decision for the senior obstetrician

Deciding on delivery

Women with a minor antepartum haemorrhage that settles are usually admitted at least until bleeding has stopped, because a small bleed can be the herald of a large one. Anti-D is given, corticosteroids considered, and follow-up arranged with serial growth surveillance. Women should be advised to return immediately if bleeding recurs and told not to have intercourse until the bleeding has fully resolved.¹

Complications

Maternal

• Hypovolaemic shock and its consequences: acute kidney injury and multi-organ failure
• Disseminated intravascular coagulation, particularly after abruption or with fetal death in utero
• Postpartum haemorrhage, because a uterus infiltrated with blood (the Couvelaire uterus) contracts poorly
• Complications of massive transfusion: hypothermia, hypocalcaemia, hyperkalaemia and dilutional coagulopathy
• Emergency hysterectomy and loss of fertility
• Sheehan's syndrome - postpartum pituitary necrosis following prolonged hypotension
• Psychological sequelae, including post-traumatic stress disorder

Fetal and neonatal

• Hypoxic-ischaemic injury and stillbirth
• Fetal growth restriction, in both recurrent bleeding and unexplained haemorrhage
• Iatrogenic preterm birth and its consequences, which account for much of the perinatal morbidity
• Fetal anaemia, which is the immediate mechanism of death in vasa praevia

Red flags

Prognosis

Outcome depends almost entirely on the cause and the volume lost. Spotting and minor bleeding from a local cause carry little risk beyond the anxiety they generate, whereas massive abruption with fetal death remains a life-threatening event for the mother. Perinatal mortality in antepartum haemorrhage is driven mainly by preterm birth and by abruption.

After any antepartum haemorrhage, the remainder of the pregnancy should be treated as high risk. Serial growth scans, a low threshold for readmission, planned birth in a unit with appropriate blood bank and neonatal facilities, and a documented plan in the notes for what to do if bleeding recurs all make a measurable difference. A postnatal debrief is worth arranging: these events are frightening, and women who have had a major haemorrhage frequently carry that fear into a subsequent pregnancy.^1,4