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Epidural Haematoma or Abscess Study

Key points

  • Epidural haematoma and epidural abscess are clinically severe and can cause permanent damage unless diagnosed and treated rapidly.
  • The current incidence of both conditions is not fully known yet women are counselled regularly.
  • In the case of epidural haematoma, the potential for iatrogenic coagulopathy with LMHW is increasing. Without information about when regional analgesia is safe, women might be denied effective pain relief unnecessarily and equally, regional techniques may well be used at an inappropriate time.
  • Both conditions can affect any obstetric unit that offers regional analgesia/anaesthesia and is not limited to high-risk tertiary referral centres.

Surveillance Period

1st January 2014 - 31st December 2017


Approximately 140,000 epidurals are placed annually for labour analgesia in the UK. There are two major but rare complications which merit study as they both occur in an occult manner leading to problems with diagnosis and further management[1]. Vertebral canal haematoma is a very rare but potentially devastating complications occurring either during placement or more typically after removal of an epidural catheter. Epidural abscess formation tends to follow a slower course, with symptoms developing over several days. Diagnosis in both cases can be difficult but delay in recognition and treatment leads rapidly to permanent neurological deficit. These complications are commonly mentioned in the pre-procedure counselling given to women. Existing estimates of the incidence of epidural haematoma are based on retrospective studies or meta-analysis of the same and are obviously subject to ascertainment bias in that it is unlikely that all obstetric cases are reported in the available literature[2]. The data themselves come from studies from up to and over 20 years old and practice may have changed not least in the increasing use of Low Molecular Weight Heparin (LMWH).


To use the UK Obstetric Surveillance System (UKOSS) to describe the incidence, management and outcomes of women with an epidural haematoma or abscess in the UK and examine potential risk factors.

Research questions

  • What is the incidence of iatrogenic epidural haematoma in the obstetric population?
  • What is the immediate management and outcome?
  • What is the timing and dose of thromboprophylaxis if any?
  • What is the incidence of iatrogenic epidural abscess in the obstetric population?
  • Are there any obvious risk factors for potential infection (immunosuppression/co-existent infection)?
  • How quickly is imaging obtained and of what modality?

Case definition

All pregnant women identified as having an epidural haematoma or abscess after a regional anaesthetic technique or attempt at technique.


This study is funded by the National Institute for Academic Anaesthesia – The Obstetric Anaesthetists Association Grant.

Ethics committee approval

This study has been approved by the NRES Committee East of England - Cambridge South (study reference 12/EE/0430).

Lead Investigator

Felicity Plaat, Imperial College Healthcare.

Download the Data Collection Form (DCF)

UKOSS Epidural Haematoma


  1. ^ Moen V., Irestedt L., Neurological complications following central neuraxial blockades in obstetrics. Current Opinion in Anesthesiology, 2008 Jun; 21(3):275-80.
  2. ^ Ruppen W., Derry S., McQuay H., Moore R., Incidence of epidural hematoma, infection, and neurological injury in obstetric patients with epidural analgesia/anesthesia. Anesthesiology, 2006 Aug; 105(2):394-9.

Updated: Tuesday, 17 January 2023 18:15 (v14)

Contact us

For more information about UKOSS, please view the contact details page