Case of the Month #45 Major Obstetric Haemorrhage - Part 1

Published 02/11/2023

What is Major Obstetric Haemorrhage (MOH)?

Obstetric haemorrhage is bleeding occurring from the genital tract or uterus in the antepartum, intrapartum or postpartum period. 

Antepartum haemorrhage (APH) is bleeding occurring from 24 weeks gestation up until the birth of the baby. This complicates between 3% and 5% of all pregnancies. 

  • Minor APH - blood loss of less than 50 ml that has settled. 

  • Major APH - blood loss of 50- 1000 ml without clinical signs of shock. 

  • Massive APH - blood loss of > 1000 ml and/ or clinical signs of shock. 

Postpartum haemorrhage (PPH) is the most common cause of MOH. Primary PPH occurs within the first 24 hours following delivery, and secondary PPH occurs between 24 hours and 12 weeks following delivery.  

The traditional WHO/ RCOG definitions of primary PPH are: 

  • Minor PPH - blood loss of > 500 ml following vaginal delivery (> 1000 ml following caesarean delivery), without clinical signs of shock 

  • Major PPH - blood loss of > 1000 ml following vaginal delivery (> 1500 ml in theatre), and/ or clinical signs of shock. Major PPH is further subdivided into moderate (1000- 2000 ml) and severe (> 2000 ml). 

MOH is generally accepted to be blood loss of > 1500 ml (> 2000 ml in theatre), with or without clinical signs of shock. 

The All-Wales Guideline for the Prevention and Management of Postpartum Haemorrhage, (OBS Cymru Quality and Safety Sub Group of Maternity Network Wales) breaks PPH down into stages: 

  • Stage 1- 500–999 ml  

  • Stage 2- 1000-1499ml  

  • Stage 3- >1500ml (major obstetric haemorrhage) 

It is important to recognise that in women with a low body weight (e.g. < 55kg), smaller volumes of blood loss may lead to shock and be clinically significant.