Antepartum haemorrhage

Definition

• Antepartum haemorrhage is vaginal bleeding in late pregnancy from 20 weeks of gestation but before the birth of the baby.

Occurrence & epidemiology

Epidemiology

• It occurs in 3–4% of pregnancies; placental abruption, at about 30%, is the commonest life-threatening cause, and placenta praevia accounts for about 20%.

Aetiopathogenesis

Aetiology and risk factors

• The commonest cause is the bloody show at the onset of labour; more serious, less common causes are placental abruption, placenta praevia, vasa praevia and uterine rupture.

Clinical features

Clinical features and complications

• Placenta praevia typically bleeds suddenly and painlessly with bright red blood and little or no uterine tenderness.
• In abruption the uterus is painful, tender and often tense; the blood is dark, clotted or bright red, and signs of fetal compromise such as bradycardia, late decelerations or a sinusoidal pattern may occur.
• Because part of the bleeding may be concealed between placenta and uterine wall, visible bleeding does not reliably reflect blood loss; haemorrhagic shock and disseminated intravascular coagulation may occur.
• In vasa praevia the blood is fetal, so even a small blood loss can cause fetal death.

Diagnosis

• Every bleed in late pregnancy requires pelvic ultrasound; normal placental position and normal cord insertion exclude placenta praevia and vasa praevia.
• Placental abruption cannot be reliably shown on ultrasound and is diagnosed clinically.

Keep learning in the app

Further reading (selection)

1. StatPearls: Placenta Previa (NCBI Bookshelf)
2. StatPearls: Placental Abruption (NCBI Bookshelf)
3. MSD Manual Professional Edition: Vaginal Bleeding During Late Pregnancy

Cross-references