Evidence map›Paper›PMID 41400660›Full record

ArticleInternational urogynecology journal2026

The Association Between Episiotomy and Obstetrical Anal Sphincter Injuries Among Vacuum-Assisted Vaginal Deliveries: A Population-Based Retrospective Canadian Cohort Study.

Chelsea Harris, Christy G Woolcott, Amy Dodge, Victoria Allen, Aisling Clancy, Jocelyn Stairs

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Article in International urogynecology journal, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

6 authors.

Chelsea HarrisDepartment of Obstetrics and Gynaecology, Dalhousie University, 5850/5980 University Avenue, P.O. Box 9700, Halifax, NS, B3K 6R8, Canada.
Christy G WoolcottDepartment of Obstetrics and Gynaecology, Dalhousie University, 5850/5980 University Avenue, P.O. Box 9700, Halifax, NS, B3K 6R8, Canada.
Amy DodgeFaculty of Medicine, Dalhousie University, Halifax, Canada.
Victoria AllenDepartment of Obstetrics and Gynaecology, Dalhousie University, 5850/5980 University Avenue, P.O. Box 9700, Halifax, NS, B3K 6R8, Canada.
Aisling ClancyDepartment of Obstetrics and Gynecology, University of Ottawa, Ottawa, Canada.
Jocelyn StairsDepartment of Obstetrics and Gynaecology, Dalhousie University, 5850/5980 University Avenue, P.O. Box 9700, Halifax, NS, B3K 6R8, Canada. jocelyn.stairs@dal.ca.ORCID 0000-0002-6748-2310

Funding

Nova Scotia Health Research Foundation 2022-2330
6 · The paper itself

Abstract

introduction and hypothesisVacuum-assisted vaginal deliveries (VAVD) represent a growing proportion of operative vaginal deliveries. Mediolateral episiotomy in patients undergoing VAVD has been shown to reduce obstetrical anal sphincter injuries (OASIS) in some settings; however, results of Canadian studies have been conflicted, and the practice has not been widely adopted by Canadian providers. The objective of this study was to estimate the association between episiotomy and OASIS among patients undergoing VAVD in a Canadian cohort.

methodsA population-based, retrospective cohort of patients who underwent VAVD at term of non-anomalous, singleton, vertex fetuses between 2005 and 2023 were identified using the  Nova Scotia Atlee Perinatal Database. Augmented inverse probability weighting analyses were used to estimate risk ratios (RR) with 95% confidence intervals (CI) adjusting for confounding variables, overall and stratified by length of the second stage of labour and parity.

resultsOf 8407 VAVD, OASIS occurred in 970 (10.3%). Episiotomy was performed in 3780 (45.0%) VAVD. Overall, episiotomy was not found to be associated with OASIS risk (RR 0.94, 95% CI 0.83-1.07). Among individuals with a total second stage ≥ 60 min (RR 0.86, 95% CI 0.75-0.99) and an active phase ≥ 60 min (RR 0.60, 95% CI 0.34-1.06), episiotomy was associated with decreased OASIS risk. When stratified by parity, episiotomy was associated with reduced OASIS risk in nulliparous (RR 0.86, 95% CI 0.75-0.99) and increased risk in parous individuals (RR 1.37, 95% CI 0.99-1.90).

conclusionsAmong patients undergoing VAVD, episiotomy was protective against OASIS in certain populations, including nulliparous individuals and those with longer second stage of labour.

Indexed as

Anal CanalEpisiotomyVacuum Extraction, ObstetricalAdultFemaleHumansNova ScotiaPregnancyRetrospective StudiesYoung AdultEpisiotomyObstetrical anal sphincter injurySecond stage of labourVacuum assisted vaginal delivery

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.