The role of mediolateral episiotomy during labour. Analysis of risk factors for obstetric anal sphincter tears

• Published in: Acta obstetricia et gynecologica Scandinavica Vol. 85; no. 7; pp. 856 - 860
• Main Authors: Aukee, Pauliina, Sundström, Helena, Kairaluoma, Matti V.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Informa UK Ltd 01.01.2006; Blackwell Publishing Ltd; Taylor & Francis
• Subjects: Adult; Anal Canal - injuries; anal sphincter tear; Biological and medical sciences; Case-Control Studies; Delivery. Postpartum. Lactation; Episiotomy; Female; Finland - epidemiology; Gynecology. Andrology. Obstetrics; Humans; Injury Severity Score; Lacerations - epidemiology; Lacerations - etiology; Lacerations - pathology; Lacerations - prevention & control; Medical sciences; Obstetric Labor Complications - epidemiology; Obstetric Labor Complications - etiology; Obstetric Labor Complications - pathology; Obstetric Labor Complications - prevention & control; Odds Ratio; Pregnancy; Pregnancy Outcome; Retrospective Studies; Risk Factors; vacuum extraction; Vacuum Extraction, Obstetrical - adverse effects; Finland; Episiotomy; vacuum extraction; Gynecology; Break; Risk analysis; Labor; Obstetrics; Vacuum extractor; Anal sphincter; Pregnancy; Obstetrical technique; Risk factor; anal sphincter tear; Extraction; Delivery
• ISSN: 0001-6349; 1600-0412
• DOI: 10.1080/00016340500408283

Background. To determine risk factors for third-degree and complete third- or fourth-degree anal sphincter tears in vaginal delivery. Methods. This is a retrospective comparative study. Fifty-three women who had sustained an anal sphincter tear were compared with 9,178 women without such a complication between August 1997 and October 2001. Obstetric data was collected from an electronic database. The main outcome measures were odds ratios. Results. In the whole study population, odds ratios (ORs) for third-degree tears were: primiparity, 8.34 (95% confidence interval [CI] 3.98-17.48); vacuum extraction, 5.22 (95% CI 2.69-10.13); parietal presentation, 3.97 (95% CI 1.16-13.64); and birth weight >4,000 g, 3.77 (95% CI 2.11-6.68); and for complete third- or fourth-degree tears odds ratios were 5.42, 2.98, 5.64, and 3.01, respectively. In multivariate analysis, mediolateral episiotomy appeared to be protective as regards third-degree tears (OR 0.37 [95% CI 0.2020-0.70]). Conclusions. Vacuum-assisted vaginal delivery bears an increased risk of third-degree anal sphincter tears in a maternity unit where forceps are not used. Restricted use of mediolateral episiotomy may have a protective effect on the perineum.