The loss of >500 ml of blood per-vagina within 24 hours of delivery

Aetiology

The causes for primary post-partum haemorrhage can be broadly categorised by the 4 T’s - tone, tissue, trauma and thrombin:

Tone

• Refers to uterine atony - the most common cause of primary PPH
• This is where the uterus fails to contract adequately following delivery, due to a lack of tone in the uterine muscle

Tissue

• Refers to the retention of placental tissue which prevents the uterus from contracting
• It is the 2nd most common cause of primary PPH

Trauma

• Refers to damage sustained to the reproductive tract during delivery (e.g. vaginal tears, cervical tears)

Thrombin

• Refers to coagulopathies and vascular abnormalities which increase the risk of primary PPH
  • Vascular - placental abruption, hypertension, pre-eclampsia
  • Coagulopathies - von Willebrand’s disease, haemophilia A/B, ITP or acquired coagulopathy i.e. DIC, HELLP

Clinical features

Symptoms

• Bleeding from the vagina
• If there is substantial blood loss, the patient may complain of dizziness, palpitations, and shortness of breath

Signs

• General examination may reveal haemodynamic instability with tachypnoea, prolonged capillary refill time, tachycardia, and hypotension
• Abdominal examination may show signs of uterine rupture i.e. palpation of fetal parts as it moves into the abdomen from the uterus