Open Access Open Badges Research article

Perineal Assessment and Repair Longitudinal Study (PEARLS): a matched-pair cluster randomized trial

Khaled M K Ismail1*, Christine Kettle2, Sue E Macdonald3, Sue Tohill4, Peter W Thomas5 and Debra Bick6

Author Affiliations

1 Professor of Obstetrics and Gynaecology, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, West Midlands, B15 2TT, UK

2 Professor of Women’s Health Staffordshire University, Blackheath Lane, Stafford, Staffordshire ST18 0AD, UK

3 Lead Midwife for Education, (until Dec 2012) College of Midwives, 15 Mansfield Street, London WIG 9NH, UK

4 Midwife, West Midlands (South) Comprehensive Local Research Network, University Hospitals Coventry and Warwickshire NHS Trust, University Hospital, Clifford Bridge Road, Coventry CV2 2DX, UK

5 Professor of Healthcare Statistics and Epidemiology, Bournemouth University, Clinical Research Unit, School of Health and Social Care, R506A Royal London House, Christchurch Road, Bournemouth, Dorset BH1 3LT, UK

6 Professor of Evidence Based Midwifery Practice, Kings College London, Florence Nightingale School of Nursing and Midwifery, 57 Waterloo Road, London SE1 8WA, UK

For all author emails, please log on.

BMC Medicine 2013, 11:209  doi:10.1186/1741-7015-11-209

Published: 23 September 2013



Perineal trauma during childbirth affects millions of women worldwide every year. The aim of the Perineal Assessment and Repair Longitudinal Study (PEARLS) was to improve maternal clinical outcomes following childbirth through an enhanced cascaded multiprofessional training program to support implementation of evidence-based perineal management.


This was a pragmatic matched-pair cluster randomized controlled trial (RCT) that enrolled women (n = 3681) sustaining a second-degree perineal tear in one of 22 UK maternity units (clusters), organized in 11 matched pairs. Units in each matched pair were randomized to receive the training intervention either early (group A) or late (group B). Outcomes within each cluster were assessed prior to any training intervention (phase 1), and then after the training intervention was given to group A (phase 2) and group B (phase 3). Focusing on phase 2, the primary outcome was the percentage of women who had pain on sitting or walking at 10 to 12 days post-natal. Secondary outcomes included use of pain relief at 10 to 12 days post-natal, need for suture removal, uptake and duration of exclusive breastfeeding, and perineal wound infection. Practice-based measures included implementation of evidence into practice to promote effective clinical management of perineal trauma. Cluster-level paired t-tests were used to compare groups A and B.


There was no significant difference between the clusters in phase 2 of the study in the average percentage of women reporting perineal pain on sitting and walking at 10 to 12 days (mean difference 0.7%; 95% CI −10.1% to 11.4%; P = 0.89). The intervention significantly improved overall use of evidence-based practice in the clinical management of perineal trauma. Following the training intervention, group A clusters had a significant reduction in mean percentages of women reporting perineal wound infections and of women needing sutures removed.


PEARLS is the first RCT to assess the effects of a ‘training package on implementation of evidence-based perineal trauma management. The intervention did not significantly improve the primary outcome but did significantly improve evidence-based practice and some of the relevant secondary clinical outcomes for women.

Trial registrations


NIHR UKCRN portfolio no: 4785.

Childbirth; Perineum; Trauma; Cluster RCT; Quality improvement