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OASI Care Bundle Project: Background

Background and history of the OASI Care Bundle project

What is OASI?

An OASI is an obstetric anal sphincter injury which can occur during vaginal birth. The long-term consequences of OASI include anal incontinence and dyspareunia which can result in significant emotional and medical burden to women.


Population-based studies from Scandinavian countries and Canada identified an increase in the occurrence of OASI. In the past 10 years, rates of OASI have also increased in England. This trend towards an increasing incidence of third or fourth degree perineal tears does not necessarily indicate poor-quality care. Tearing is a complex issue which could be influenced by a range of factors including; advanced maternal age at first birth, larger maternal BMI and birth weight of the baby, instrumental delivery and better detection and reporting.

However, as OASI can dramatically impact the short and long-term health of women influencing decisions about future births, prevention and management of OASI is a priority. 


Aims of the programme

The initial aims of the programme were:

  • To investigate and identify patterns of care, morbidity and outcomes related to women who suffered an OASI in Great Britain
  • To raise awareness about the incidence of OASI among all health professionals involved in maternity care
  • To review the literature on clinical interventions for the prevention of OASI
  • To produce an evidence-based care bundle to support clinical practice
  • To pilot the care bundle in a sample of units

This project focused on OASI resulting from labour and vaginal birth. The project excluded the management and prevention of OASI resulting from gynaecological/urological procedures. It also excluded considerations on repair techniques and related co-morbidities. 


Watch: The project team on scaling up the OASI Care Bundle Quality Improvement Project



Recruitment of the sites is complete, with both a Midwifery and an Obstetric Champion volunteering to lead the programme from within each hospital. Support from local clinical champions, opinion leaders and professional organisations, as well as patient and public involvement and continuous monitoring and feedback, will help ensure that interventions are acceptable to women and health care professionals.

The programme has run for 2.5 years. The evaluation of the programme includes evaluation of the impact of the OASI care bundle on clinical practice and clinical outcomes. Results will be shared through publications.

This project focuses on OASI resulting from labour and vaginal birth. The project excludes the management and prevention of OASI resulting from gynaecological/urological procedures. It also excludes considerations on repair techniques and related co-morbidities.



The programme included the following activities:


Outputs of the OASI project

Analysis of secondary care data


OASI Care Bundle

Following the OASI ‘Summit’ held at the RCOG on 1 May 2014, the RCOG committed to reducing OASI throughout the UK.

The RCOG have been working with the Royal College of Midwives to increase awareness of OASI incidence and risks among health professionals involved in maternity care and to develop tools to improve the prevention and management of severe perineal tearing. A national group of experts have been involved in the development of the OASI Care Bundle.

The elements of the OASI bundle include informing each woman about OASI and what can be done to minimize her risk, performing an episiotomy (a cut in the perineum to assist birth and prevent tears) when required, using the hands to enable perineal protection at the time of birth and a thorough examination after birth to detect tears not all of which will be immediately obvious. All elements of the care bundle are underpinned by good communication with the woman before, during and after birth.

We have developed and piloted an intervention package which brings together the care bundle, a skills development module, and campaign materials. Over the next couple of years, we will be scaling up this project, implementing the intervention in 16 sites across Great Britain and looking at the outcomes over this period.


OASI Care Bundle

Find out more


Contact us

For more information about the OASI care bundle, please or call +44 20 7772 6224.