Does mediolateral or lateral episiotomy reduce the risk of anal incontinence in primiparous women undergoing an operative vaginal delivery? A systematic review and meta-analysis protocol

Does mediolateral or lateral episiotomy reduce the risk of anal incontinence in primiparous women undergoing an operative vaginal delivery? 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A systematic review and meta-analysis protocol Monika Zinkeviciute, Océane Pécheux, Begoña Martinez Tejada, Nicolas Silvestrini, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8039598/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 4 You are reading this latest preprint version Abstract Background: Obstetric anal sphincter injuries are the leading cause of anal incontinence. Primiparous women undergoing assisted vaginal deliveries are at the greatest risk of experiencing these injuries. Mediolateral or lateral episiotomy has been identified as a potential intervention to reduce this risk. However, anal incontinence, the more clinically significant outcome, requires further exploration. The aim of this systematic review is to evaluate whether mediolateral/lateral episiotomy in primiparous women undergoing assisted vaginal delivery reduces the incidence of anal incontinence, and to determine the corresponding number-needed-to-treat (NNT). Methods: A systematic search of the literature will be conducted in the following information sources: PubMed, The Cochrane Library, EMBASE, Google Scholar and the references list of eligible articles. Articles will be screened against the inclusion and exclusion criteria at the level of the title, abstract and full text. Full-text articles that meet the inclusion criteria will then be assessed independently by two investigators. A sensitivity analyses will be performed. If enough studies report relevant data and the heterogeneity index (I²) is <75%, a meta-analysis will be conducted; otherwise, only a descriptive synthesis will be provided. Risk of bias will be assessed using validated tools, and the overall quality of evidence will be evaluated. PROSPERO registration number: CRD420251076735 primiparous episiotomy anal incontinence instrumental delivery obstetric anal sphincter injuries Background Anal incontinence (AI), defined as the involuntary loss of stool and/or gas (1), is not merely a physical condition. It can also have a profound psychological and social impact on women, often resulting in shame, and low self-esteem, as well as restricting both social and intimate spheres of life (2,3). Even short-term AI, at four months postpartum, is associated with significantly higher rates of depression: 50.0% in women with fecal incontinence, 26.6% in those with flatus incontinence, and 17.2% in continent women (4). In women of reproductive age, the most common cause of AI is obstetric anal sphincter injuries (OASIS) (5), which includes third-degree perineal tears involving the anal sphincter and fourth-degree tears extending through the anal epithelium (6,7). A meta-analysis revealed that up to 38% of women experience AI after primary sphincter repair (5). Even 20 years after childbirth, bothersome fecal incontinence persists in 3.3% of women without OASIS, and in 10.4% of those with OASIS — suggesting that, despite repair, anal sphincter injury multiplies the long-term risk of fecal incontinence by more than threefold (2). Episiotomy is a well-established method for preventing OASIS (8,9). The three most common techniques are midline episiotomy (mainly used in the United States of America), mediolateral episiotomy (MLE) (widely practiced in Europe (10)) and lateral episiotomy (LE) (8). However, routine use of episiotomy is not recommended for spontaneous vaginal deliveries (11) but may be considered for operative deliveries (12). The role of episiotomy remains debated in operative vaginal deliveries, especially in primiparous women — the group at highest risk for OASIS (13–15). The incidence of OASIS ranges from 1.5% to 28.1% following vacuum extraction (VE) (16), and is even higher with forceps or spatula-assisted deliveries (14–18). A recent meta-analysis including 703,977 patients found that the risk of OASIS was lower in primiparous women who underwent MLE or LE during VE (OR 0.5; 95% CI 0.4–0.8) or forceps deliveries (OR 0.3; 95% CI 0.2–0.6). The NNT to prevent one OASIS was 23 for VE and eight for forceps deliveries (17). A Swedish randomized controlled trial reported a similar benefit, with an NNT of 14.3 (95% CI 8.6–40.0) for preventing OASIS in primiparous women undergoing VE (8). Given that AI tends to appear or worsen over time and that its causes extend beyond sphincter damage to include nerve injuries, puborectalis muscle avulsions, and other pelvic floor dysfunctions, it is essential to assess whether MLE or LE in primiparous women undergoing vaginal delivery could also reduce the risk of subsequent AI — which is a more clinically meaningful outcome. Since AI prevalence increases with age (18) and other risk factors (19–21), and given that episiotomy carries its own potential complications, such an evaluation —both short- and long-term — could therefore provide valuable evidence to guide clinical practice and improve maternal health outcomes. Methods/Design The methodology is based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines PRISMA-P 2015 (22). The study will be conducted from 1 December 2025 to 1 December 2026. A PICO approach will be followed: Population: Primiparous women undergoing operative vaginal delivery Intervention: MLE/LE Comparator: No episiotomy Outcome: Incidence of anal incontinence (AI) in primiparous women after operative vaginal delivery (i.e. first vaginal delivery) Inclusion criteria Types of studies We will include systematic reviews of published and non-published randomized controlled trials (RCTs), randomized and non-randomized controlled trials, prospective and retrospective observational studies. We will exclude case reports, case series, conference abstracts, animal studies. Types of participants We will include studies reporting on primiparous women who underwent a first vaginal delivery being operative. Women with a history of caesarean section but no vaginal delivery, who underwent an assisted vaginal delivery, are also eligible. We will exclude primiparous and multiparous women undergoing caesarean section or spontaneous vaginal delivery. Types of intervention We will include studies using lateral or mediolateral episiotomy. If data is mixed, we will extract data of MLE/LE. We will exclude trials using midline episiotomy, or if unspecified. Comparator intervention The control intervention will be no episiotomy performed. Outcomes Primary outcome The main outcome measure of effect will be the absolute risk difference in the occurrence of AI – any report of gas and/or liquid loss after an operative delivery (1). For articles reporting the absolute risk difference, we will extract absolute risk difference as well as its standard error, if available, or its confidence interval, based on which we will determine the standard error. For articles reporting a risk ratio but not the absolute risk difference, we will estimate the absolute risk difference using the baseline risk (i.e., the event rate in the control group). If the baseline risk is not directly reported, we will attempt to derive it from the available data or use an appropriate external estimate. The minimum clinically important difference will be considered, based on an expert agreed threshold of at least 1%. Secondary outcomes Secondary outcomes measures of effect will be the absolute risk difference in the occurrence of: Post-partum AI - gas and/or liquid loss lasting ≤12 months after the delivery. Long-term AI - gas and/or liquid loss lasting more than 12 months after the delivery. Post-partum faecal incontinence (FI) - complaint of involuntary loss of faeces (solid and/or liquid) lasting ≤12 months after the delivery. Long term FI - complaint of involuntary loss of faeces (solid and/or liquid) lasting longer than 12 months after delivery. For articles reporting the absolute risk difference, we will extract absolute risk difference as well as its standard error, if available, or its confidence interval, based on which we will determine the standard error. For articles reporting a risk ratio but not the absolute risk difference, we will estimate the absolute risk difference using the baseline risk (i.e., the event rate in the control group). If the baseline risk is not directly reported, we will attempt to derive it from the available data or use an appropriate external estimate. The minimum clinically important differences will be considered clinically significant, based on an expert agreed threshold of at least 1%. To note, AI can be in the included studies the primary outcome or not, but this will be specified. Search strategy We will use the following information sources: PubMed, The Cochrane Library, EMBASE, Google Scholar (for the grey literature). We will scan the list of references of eligible studies. The languages will be restricted to the Latin alphabet only. Correspondingly, the search will be restricted to the following languages: English, German, French, Spanish, Portuguese, Italian, Dutch, Swedish, Finnish, Norwegian and Turkish. For articles in other languages than the ones fully understood by at least one of the investigators (French, English, Spanish or Italian) we will use DeepL online translator or contact the authors. Searches will not be restricted by the date. Searches will be re-run during the last month prior to the final analysis. We will use the combination of free-text keywords, medical subject headings (MeSH) in PubMed and Emtree terms in EMBASE (Table 1). Boolean operators AND and OR will be used, when suitable, to combine search. Search strategies will be customised for each electronic database according to their individual subject headings, syntax and searching structure. A draft search strategy will be developed with the assistance of an experienced medical librarian and piloted to ensure sensitivity. The final search strategies for all databases will be provided as an appendix in the full review. Data extraction Firstly, two people will screen the records independently for inclusion. The results will then be exported to the Zotero reference management system and de-duplicated. Full-text articles which meet the inclusion criteria will then be assessed independently by two investigators. Secondly, a manual search of the references from selected studies will be conducted to identify other relevant studies. We will obtain the full texts of the retrieved studies for assessment. Studies that do not meet the inclusion criteria will be considered irrelevant and will be discarded. Some pilot searches will be performed before selecting the definitive set of databases, to ensure that they are wide-ranging and effective enough to identify the studies of interest. Any disagreements regarding article selection will be resolved through group discussion. Two senior researchers will be involved in this process. We will follow the PRISMA 2020 recommended flowchart (23). We will use Covidence software to analyse the data and record the decisions made. The extracted data will include study characteristics and patient-related information, as well as details regarding episiotomy and operative delivery practices (Table 2). Risk of bias We will assess the risk of bias in RCTs using the Cochrane Risk-of-Bias tool for randomised trials (RoB 2) (24) and by the Risk Of Bias in Non- randomised Studies-of Interventions (ROBINS-I) tool for non-randomised studies, including observational studies (25). We will assess the risk of bias at both the outcome and study level. Two reviewers will be involved in the quality assessment. Any disagreement will be resolved by group discussion, including two other researchers, and a consensus decision will be reached. We anticipate some heterogeneity in episiotomy technique and use across studies, variability in follow-up duration, and potential confounders such as pre-existing pelvic floor dysfunction and neonatal birth weight. To address these limitations, we plan to perform sensitivity analyses. In case the I 2 (heterogeneity index) would be greater than 75%, we would only perform a descriptive metanalysis and not an analytical one, unless we identify a single study, with inadequate methodology, that we can exclude. Strategy of data synthesis For each included study, we will compile a table of the characteristics of the study, the patients, the intervention and the operative delivery. The findings will be summarised either narratively or quantitatively (i.e. meta-analysis). Only evidence from similar study types (i.e RCT alone) will be pooled for analysis. We will use a random effects statistical model. We will assess the overall quality of the evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) working group’s criteria recommended (26). To assess the certainty (or confidence) of the body of evidence for an outcome, we will review and report on the following: study design, targeted sample population, clear definition of outcome, period of follow-up, sample size calculation and its completeness, statistics plan and study power. Any disagreements surrounding the eligibility of studies for overall study quality will be discussed and resolved through consensus-based discussion. Discussion Episiotomy is a subject of ongoing debate, often associated with mixed patient experiences and potential complications. In our view, it is essential to assess whether this procedure provides long-term protection against AI—an outcome that directly impacts quality of life and is of primary concern for patients. While sphincter injuries are widely studied, their clinical relevance is ultimately tied to whether they result in symptoms such as AI. For shared decision-making to be meaningful, patients must be informed about the true long-term benefits and risks of episiotomy, particularly in terms of functional outcomes. It is also important to determine how long any potential protective effect of episiotomy might last, especially considering that AI becomes more common with advancing age. It is crucial to understand which subgroups of women may benefit from this intervention, particularly for those who are already affected by or at high risk for AI throughout their lifetimes. We anticipate that relatively few studies have directly addressed AI as an outcome, with most focusing on sphincter injuries instead. By conducting a review that centers on clinically meaningful outcomes, rather than statistically significant differences alone, and by establishing minimum clinically important differences (MCIDs) in advance, our aim is to highlight what truly matters to patients and clinicians. This approach may also help guide the design and focus of future studies. Furthermore, clearly defining outcomes and systematically identifying and accounting for confounding factors will contribute to improving the quality and applicability of future research on this topic. Abbreviations AI – anal incontinence CI - confidence interval FI – fecal incontinence GRADE - Grading of Recommendations Assessment, Development and Evaluation LE – lateral episiotomy meSH – medical subject headings MLE – mediolateral episiotomy NNT – number needed to treat OASIS – obstetric anal sphincter injuries OR – odds ratio PICO - Population, Intervention, Comparison, and Outcome PRISMA – Preferred Reporting Items for Systematic Reviews and Meta-Analyses RCT – randomized controlled trial ROB-2 - risk-of-bias tool ROBINS - Risk of Bias in Non- randomized Studies-of Interventions RR- relative risk SD - standard deviation VE – vacuum extraction WHO – World Health Organisation Declarations Ethics approval and consent to participate not required for a literature review. Consent for publication: not applicable. Availability of data and materials: The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. Competing interests: The authors declare that they have no competing interests. Funding: No funding. Authors' contributions: Monika Zinkeviciute, Océane Pécheux: conception, design of the work; have drafted and revised the protocol. Aurore Fehlmann, Caroline Daelemans: conception, design of the work; have substantively revised the protocol; will substantively revise the manuscript. Caroline Daelemans is the guarantor of the review. Nicolas Silvestrini: have substantively revised the protocol (statistics and methodology). Sophie Gallot: search strategy. Begoña Martinez de Tejada: design of the work and revised the protocol. Use of artificial intelligence tools: Some sections of this manuscript were edited with the assistance of AI-based language tools, including ChatGPT (OpenAI) and DeepL Translator, to improve clarity and language fluency. All content was subsequently reviewed and verified by the authors. 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Sideris M, McCaughey T, Hanrahan JG, Arroyo-Manzano D, Zamora J, Jha S, et al. Risk of obstetric anal sphincter injuries (OASIS) and anal incontinence: A meta-analysis. Eur J Obstet Gynecol Reprod Biol. 2020 Sep;252:303–12. Fernando RJ, Sultan AHH, Kettle C, Thakar R, Radley S. Methods of repair for obstetric anal sphincter injury. In: The Cochrane Collaboration, editor. Cochrane Database of Systematic Reviews [Internet]. Chichester, UK: John Wiley & Sons, Ltd; 2006 [cited 2023 Feb 5]. p. CD002866.pub2. Available from: https://doi.wiley.com/10.1002/14651858.CD002866.pub2 Sultan AH, Monga A, Lee J, Emmanuel A, Norton C, Santoro G, et al. An International Urogynecological Association (IUGA)/International Continence Society (ICS) joint report on the terminology for female anorectal dysfunction. Int Urogynecology J. 2017 Jan;28(1):5–31. Bergendahl S, Ankarcrona V, Leijonhufvud A, Hesselman S, Karlstrom S, Kopp Kallner H, et al. Lateral episiotomy versus no episiotomy to reduce obstetric anal sphincter injury in vacuum-assisted delivery in nulliparous women: study protocol on a randomised controlled trial. BMJ Open. 2019;9(3):e025050. Verghese TS, Champaneria R, Kapoor DS, Latthe PM. Obstetric anal sphincter injuries after episiotomy: systematic review and meta-analysis. Int Urogynecology J. 2016;27(10):1459–67. Barjon K, Mahdy H. Episiotomy [Internet]. StatPearls [Internet]. StatPearls Publishing; 2022 [cited 2023 Feb 19]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK546675/ Jiang H, Qian X, Carroli G, Garner P. Selective versus routine use of episiotomy for vaginal birth. Cochrane Database Syst Rev [Internet]. 2017 [cited 2023 May 15];(2). Available from: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD000081.pub3/full Ubom AE, Barnea ER, DiSimone N, Mueller M, Beyeza-Kashesya J, Nunes I, et al. FIGO good practice recommendations: Assisted vaginal birth and the second stage of labor. 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Okeahialam NA, Wong KW, Jha S, Sultan AH, Thakar R. Mediolateral/lateral episiotomy with operative vaginal delivery and the risk reduction of obstetric anal sphincter injury (OASI): A systematic review and meta-analysis. Int Urogynecology J. 2022 Jun;33(6):1393–405. Mack I, Hahn H, Gödel C, Enck P, Bharucha AE. Global Prevalence of Fecal Incontinence in Community-Dwelling Adults: A Systematic Review and Meta-analysis. Clin Gastroenterol Hepatol Off Clin Pract J Am Gastroenterol Assoc. 2024 Apr;22(4):712-731.e8. Maeda K, Koide Y, Katsuno H, Hanai T, Masumori K, Matsuoka H, et al. Prevalence and Risk Factors of Anal and Fecal Incontinence in Japanese Medical Personnel. J Anus Rectum Colon. 2021;5(4):386–94. Bharucha AE, Zinsmeister AR, Locke GR, Seide BM, McKeon K, Schleck CD, et al. Risk factors for fecal incontinence: a population-based study in women. Am J Gastroenterol. 2006 Jun;101(6):1305–12. Geynisman-Tan J, Kenton K, Leader-Cramer A, Dave B, Bochenska K, Mueller M, et al. Anal Penetrative Intercourse as a Risk Factor for Fecal Incontinence. Female Pelvic Med Reconstr Surg. 2018;24(3):252–5. Shamseer L, Moher D, Clarke M, Ghersi D, Liberati A, Petticrew M, et al. Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015: elaboration and explanation. 2015 Jan 2 [cited 2025 Jul 25]; Available from: https://www.bmj.com/content/349/bmj.g7647 PRISMA statement [Internet]. [cited 2025 Aug 22]. PRISMA 2020 flow diagram. Available from: https://www.prisma-statement.org/prisma-2020-flow-diagram Sterne JAC, Savović J, Page MJ, Elbers RG, Blencowe NS, Boutron I, et al. RoB 2: a revised tool for assessing risk of bias in randomised trials. BMJ. 2019 Aug 28;l4898. Sterne JA, Hernán MA, Reeves BC, Savović J, Berkman ND, Viswanathan M, et al. ROBINS-I: a tool for assessing risk of bias in non-randomised studies of interventions. BMJ. 2016 Oct 12;i4919. GRADE Book [Internet]. [cited 2025 Jul 4]. Available from: https://book.gradepro.org/ Types of female genital mutilation [Internet]. [cited 2025 Jul 2]. Available from: https://www.who.int/teams/sexual-and-reproductive-health-and-research-(srh)/areas-of-work/female-genital-mutilation/types-of-female-genital-mutilation Tables Table 1 Key words, MeSH terms and Emtree terms used for the systematic literature review Concept 1: primiparous women undergoing an operative vaginal delivery Concept 2: mediolateral or lateral episiotomy Concept 3: anal incontinence Controlled vocabulary Controlled vocabulary Controlled vocabulary Emtree Emtree Emtree 'assisted vaginal delivery'/exp 'episiotomy'/exp 'feces incontinence'/exp 'instrumental delivery'/exp 'lateral episiotomy'/exp flatus incontinence 'obstetric forceps'/exp 'mediolateral episiotomy'/exp 'operative vaginal delivery'/exp Controlled vocabulary Controlled vocabulary Controlled vocabulary MeSH MeSH MeSH "Extraction, Obstetrical"[Mesh] "Episiotomy"[Mesh] "Fecal Incontinence"[Mesh] "Obstetrical Forceps"[Mesh] Free text Free text Free text Keywords Keywords Keywords (kiwi NEXT/2 (vacuum OR cup*)) lateral episiotom* ((anal OR anus OR f$ecal OR feces OR stool OR bowel OR rect*) NEXT/1 (incontinence* OR continence*)) assisted deliver* mediolateral episiotom* Cleveland Clinic score* forceps St-Mark* NEXT/2 score* instrument* deliver* vaizey score* metallic cup* omnicup* operative deliver* spatula* vacuum Table 2 Data collection – characteristics Study characteristics Patient characteristics The intervention (episiotomy) Operative delivery Title Study design Study duration Sample size Inclusion and exclusion criteria Authors and year Study country Body mass index or weight and height Ethnicity Age Gestational age in weeks Number of fetuses Medical history of: Crohn’s disease or ulcerative colitis, pelvic chemotherapy, pre-existing chronic diarrhea or rectal urgency, Ehlers-Danlos syndrome, presence of any other perianal lesion (perianal fissure, or anorectal or rectovaginal fistula) Female genital mutilation - defined as any procedure involving partial or total removal of the external female genitalia without medical indication. Classified in according to the WHO (World Health Organisation) female genital mutilation classification (27) Perineal body length OASIS Fetal weight Fetal presentation: breech or cephalic (occiput anterior or posterior) MLE or LE Angle and length of episiotomy (incision) Angle and length of episiotomy (suture) Type of instrument used – spatula, forceps (rotational versus non-rotational) and if possible, their type (Kielland, Pageot, Naegele, Tarnier, Piper, Suzor, etc) ventouse (metallic or plastic cup) Operator’s experience (years) Duration of the second phase of labor (total duration and specific duration of active pushing phase) Epidural Use of oxytocin during labour Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8039598","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Study protocol","associatedPublications":[],"authors":[{"id":561090695,"identity":"272f78e8-4c73-401b-84ed-614a0ad172c7","order_by":0,"name":"Monika 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18:36:55","extension":"png","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":215204,"visible":true,"origin":"","legend":"","description":"","filename":"Table1.png","url":"https://assets-eu.researchsquare.com/files/rs-8039598/v1/898f7c9d30aee75da1532718.png"},{"id":98544615,"identity":"f2305731-b77b-4e14-8856-140b47acdbe0","added_by":"auto","created_at":"2025-12-18 18:36:55","extension":"png","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":211014,"visible":true,"origin":"","legend":"","description":"","filename":"Table2.png","url":"https://assets-eu.researchsquare.com/files/rs-8039598/v1/31d39dcded1f1c783fccd07d.png"},{"id":98627160,"identity":"022bf02b-0fe9-46da-b37e-dc8c1186c2d4","added_by":"auto","created_at":"2025-12-19 17:10:10","extension":"json","order_by":3,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":8292,"visible":true,"origin":"","legend":"","description":"","filename":"6e0e0a3cf5794d759dc198517061545c.json","url":"https://assets-eu.researchsquare.com/files/rs-8039598/v1/f4a630630e822bea87db30e1.json"},{"id":98775610,"identity":"703291da-06c2-4642-8d5c-f6ba2c860a27","added_by":"auto","created_at":"2025-12-22 12:20:33","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":729918,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8039598/v1/11c14ae6-bdf9-4c0c-ba72-b8d085d4c9a4.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eDoes mediolateral or lateral episiotomy reduce the risk of anal incontinence in primiparous women undergoing an operative vaginal delivery? A systematic review and meta-analysis protocol\u003c/p\u003e","fulltext":[{"header":"Background","content":"\u003cp\u003eAnal incontinence (AI), defined as the involuntary loss of stool and/or gas\u0026nbsp;(1), is not merely a physical condition. It can also have a profound psychological and social impact on women, often resulting in shame, and low self-esteem, as well as restricting both social and intimate spheres of life\u0026nbsp;(2,3). Even short-term AI, at four months postpartum, is associated with significantly higher rates of depression: 50.0% in women with fecal incontinence, 26.6% in those with flatus incontinence, and 17.2% in continent women\u0026nbsp;(4).\u003c/p\u003e\n\u003cp\u003eIn women of reproductive age, the most common cause of AI is obstetric anal sphincter injuries (OASIS)\u0026nbsp;(5), which includes third-degree perineal tears involving the anal sphincter and fourth-degree tears extending through the anal epithelium (6,7). A meta-analysis revealed that up to 38% of women experience AI after primary sphincter repair (5). \u0026nbsp;Even 20 years after childbirth, bothersome fecal incontinence persists in 3.3% of women without OASIS, and in 10.4% of those with OASIS — suggesting that, despite repair, anal sphincter injury multiplies the long-term risk of fecal incontinence by more than threefold\u0026nbsp;(2).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eEpisiotomy is a well-established method for preventing OASIS\u0026nbsp;(8,9). The three most common techniques are midline episiotomy (mainly used in the United States of America), mediolateral episiotomy (MLE) (widely practiced in Europe\u0026nbsp;(10)) and lateral episiotomy (LE)\u0026nbsp;(8). However, routine use of episiotomy is not recommended for spontaneous vaginal deliveries\u0026nbsp;(11)\u0026nbsp;but may be considered for operative deliveries\u0026nbsp;(12).\u003c/p\u003e\n\u003cp\u003eThe role of episiotomy remains debated in operative vaginal deliveries, especially in primiparous women — the group at highest risk for OASIS\u0026nbsp;(13–15).\u0026nbsp;The incidence of OASIS ranges from 1.5% to 28.1% following vacuum extraction (VE)\u0026nbsp;(16),\u0026nbsp;and is even higher with forceps or spatula-assisted deliveries (14–18).\u003c/p\u003e\n\u003cp\u003eA recent meta-analysis including 703,977 patients found that the risk of OASIS was lower in primiparous women who underwent MLE or LE during VE (OR 0.5; 95% CI 0.4–0.8) or forceps deliveries (OR 0.3; 95% CI 0.2–0.6). The NNT to prevent one OASIS was 23 for VE and eight for forceps deliveries\u0026nbsp;(17).\u0026nbsp;A Swedish randomized controlled trial reported a similar benefit, with an NNT of 14.3 (95% CI 8.6–40.0) for preventing OASIS in primiparous women undergoing VE\u0026nbsp;(8).\u003c/p\u003e\n\u003cp\u003eGiven that AI tends to appear or worsen over time and that its causes extend beyond sphincter damage to include nerve injuries, puborectalis muscle avulsions, and other pelvic floor dysfunctions, it is essential to assess whether MLE or LE in primiparous women undergoing vaginal delivery could also reduce the risk of subsequent AI — which is a more clinically meaningful outcome. Since AI prevalence increases with age (18) and other risk factors (19–21), and given that episiotomy carries its own potential complications, such an evaluation —both short- and long-term — could therefore provide valuable evidence to guide clinical practice and improve maternal health outcomes.\u003c/p\u003e"},{"header":"Methods/Design","content":"\u003cp\u003eThe methodology is based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines PRISMA-P 2015 (22). The study will be conducted from 1 December 2025 to 1 December 2026.\u003c/p\u003e\n\u003cp\u003eA PICO approach will be followed:\u003c/p\u003e\n\u003cp\u003ePopulation: Primiparous women\u0026nbsp;undergoing operative vaginal delivery\u003c/p\u003e\n\u003cp\u003eIntervention: MLE/LE\u003c/p\u003e\n\u003cp\u003eComparator: No episiotomy\u003c/p\u003e\n\u003cp\u003eOutcome: Incidence of anal incontinence (AI) in primiparous women after operative vaginal delivery (i.e. first vaginal delivery)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInclusion criteria\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cu\u003eTypes of studies\u003c/u\u003e\u003c/p\u003e\n\u003cp\u003eWe will include systematic reviews of published and non-published randomized controlled trials (RCTs), randomized and non-randomized controlled trials, prospective and retrospective observational studies.\u0026nbsp;We will exclude case reports, case series, conference abstracts, animal studies.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cu\u003eTypes of participants\u0026nbsp;\u003c/u\u003e\u003c/p\u003e\n\u003cp\u003eWe will include studies reporting on primiparous women who underwent a first vaginal delivery being operative. Women with a history of caesarean section but no vaginal delivery, who underwent an assisted vaginal delivery, are also eligible.\u0026nbsp;We will exclude primiparous and multiparous women undergoing caesarean section or spontaneous vaginal delivery.\u003c/p\u003e\n\u003cp\u003e\u003cu\u003eTypes of intervention\u003c/u\u003e\u003c/p\u003e\n\u003cp\u003eWe will include studies using lateral or mediolateral episiotomy. If data is mixed, we will extract data of MLE/LE. We will exclude trials using midline episiotomy, or if unspecified.\u003c/p\u003e\n\u003cp\u003e\u003cu\u003eComparator intervention\u0026nbsp;\u003c/u\u003e\u003c/p\u003e\n\u003cp\u003eThe control intervention will be no episiotomy performed.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eOutcomes\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cu\u003ePrimary outcome\u003c/u\u003e\u003c/p\u003e\n\u003cp\u003eThe main outcome measure of effect will be the absolute risk difference in the occurrence of AI – any report of gas and/or liquid loss after an operative delivery\u0026nbsp;(1).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFor articles reporting the absolute risk difference, we will extract absolute risk difference as well as its standard error, if available, or its confidence interval, based on which we will determine the standard error.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFor articles reporting a risk ratio but not the absolute risk difference, we will estimate the absolute risk difference using the baseline risk (i.e., the event rate in the control group). If the baseline risk is not directly reported, we will attempt to derive it from the available data or use an appropriate external estimate.\u003c/p\u003e\n\u003cp\u003eThe minimum clinically important difference will be considered, based on an expert agreed threshold of at least 1%.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cu\u003eSecondary outcomes\u003c/u\u003e\u003c/p\u003e\n\u003cp\u003eSecondary outcomes measures of effect will be the absolute risk difference in the occurrence of:\u0026nbsp;\u003c/p\u003e\n\u003col\u003e\n \u003cli\u003e\u0026nbsp;Post-partum AI - gas and/or liquid loss lasting ≤12 months after the delivery.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e\u0026nbsp;Long-term AI - gas and/or liquid loss lasting more than 12 months after the delivery.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e\u0026nbsp;Post-partum faecal incontinence (FI) - complaint of involuntary loss of faeces (solid and/or liquid) lasting ≤12 months after the delivery.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003e\u0026nbsp;Long term FI - complaint of involuntary loss of faeces (solid and/or liquid) lasting longer than 12 months after delivery.\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003eFor articles reporting the absolute risk difference, we will extract absolute risk difference as well as its standard error, if available, or its confidence interval, based on which we will determine the standard error.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFor articles reporting a risk ratio but not the absolute risk difference, we will estimate the absolute risk difference using the baseline risk (i.e., the event rate in the control group). If the baseline risk is not directly reported, we will attempt to derive it from the available data or use an appropriate external estimate.\u003c/p\u003e\n\u003cp\u003eThe minimum clinically important differences will be considered clinically significant, based on an expert agreed threshold of at least 1%.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTo note, AI can be in the included studies the primary outcome or not, but this will be specified.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSearch strategy\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe will use the following information sources: PubMed, The Cochrane Library, EMBASE, Google Scholar (for the grey literature). We will scan the list of references of eligible studies.\u0026nbsp;The languages will be restricted to the Latin alphabet only. Correspondingly, the search will be restricted to the following languages: English, German, French, Spanish, Portuguese, Italian, Dutch, Swedish, Finnish, Norwegian and Turkish.\u0026nbsp;For articles in other languages than the ones fully understood by at least one of the investigators (French, English, Spanish or Italian) we will use DeepL online translator or contact the authors. Searches will not be restricted by the date. Searches will be re-run during the last month prior to the final analysis.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWe will use the combination of free-text keywords, medical subject headings (MeSH) in PubMed and Emtree terms in EMBASE (Table 1). Boolean operators AND and OR will be used, when suitable, to combine search. Search strategies will be customised for each electronic database according to their individual subject headings, syntax and searching structure. A draft search strategy will be developed with the assistance of an experienced medical librarian and piloted to ensure sensitivity. The final search strategies for all databases will be provided as an appendix in the full review.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData extraction\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFirstly, two people will screen the records independently for inclusion. The results will then be exported to the Zotero reference management system and de-duplicated. Full-text articles which meet the inclusion criteria will then be assessed independently by two investigators. Secondly, a manual search of the references from selected studies will be conducted to identify other relevant studies. We will obtain the full texts of the retrieved studies for assessment. Studies that do not meet the inclusion criteria will be considered irrelevant and will be discarded. Some pilot searches will be performed before selecting the definitive set of databases, to ensure that they are wide-ranging and effective enough to identify the studies of interest. Any disagreements regarding article selection will be resolved through group discussion. Two senior researchers will be involved in this process. We will follow the PRISMA 2020 recommended flowchart\u0026nbsp;(23). We will use Covidence software to\u0026nbsp;analyse\u0026nbsp;the data and record the decisions made.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe extracted data will include study characteristics and patient-related information, as well as details regarding episiotomy and operative delivery practices (Table 2).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRisk of bias\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe will assess the risk of bias in RCTs using the Cochrane Risk-of-Bias tool for randomised trials (RoB 2)\u0026nbsp;(24)\u0026nbsp;and by the Risk Of Bias in Non- randomised Studies-of Interventions (ROBINS-I) tool for non-randomised studies, including observational studies (25). We will assess the risk of bias at both the outcome and study level. Two reviewers will be involved in the quality assessment. Any disagreement will be resolved by group discussion, including two other researchers, and a consensus decision will be reached. We anticipate some heterogeneity in episiotomy technique and use across studies, variability in follow-up duration, and potential confounders such as pre-existing pelvic floor dysfunction and neonatal birth weight. To address these limitations, we plan to perform sensitivity analyses. In case the I\u003csup\u003e2\u003c/sup\u003e (heterogeneity index) would be greater than 75%, we would only perform a descriptive metanalysis and not an analytical one, unless we identify a single study, with inadequate methodology, that we can exclude.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStrategy of data synthesis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFor each included study, we will compile a table of the characteristics of the study, the patients, the intervention and the operative delivery. The findings will be summarised either narratively or quantitatively (i.e. meta-analysis). Only evidence from similar study types (i.e RCT alone) will be pooled for analysis. We will use a random effects statistical model.\u003c/p\u003e\n\u003cp\u003eWe will assess the overall quality of the evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) working group’s criteria recommended (26).\u003c/p\u003e\n\u003cp\u003eTo assess the certainty (or confidence) of the body of evidence for an outcome, we will review and report on the following: study design, targeted sample population, clear definition of outcome, period of follow-up, sample size calculation and its completeness, statistics plan and study power. Any disagreements surrounding the eligibility of studies for overall study quality will be discussed and resolved through consensus-based discussion.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eEpisiotomy is a subject of ongoing debate, often associated with mixed patient experiences and potential complications. In our view, it is essential to assess whether this procedure provides long-term protection against AI—an outcome that directly impacts quality of life and is of primary concern for patients. While sphincter injuries are widely studied, their clinical relevance is ultimately tied to whether they result in symptoms such as AI. For shared decision-making to be meaningful, patients must be informed about the true long-term benefits and risks of episiotomy, particularly in terms of functional outcomes.\u003c/p\u003e\n\u003cp\u003eIt is also important to determine how long any potential protective effect of episiotomy might last, especially considering that AI becomes more common with advancing age. It is crucial to understand which subgroups of women may benefit from this intervention, particularly for those who are already affected by or at high risk for AI throughout their lifetimes.\u003c/p\u003e\n\u003cp\u003eWe anticipate that relatively few studies have directly addressed AI as an outcome, with most focusing on sphincter injuries instead.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eBy conducting a review that centers on clinically meaningful outcomes, rather than statistically significant differences alone, and by establishing minimum clinically important differences (MCIDs) in advance, our aim is to highlight what truly matters to patients and clinicians. This approach may also help guide the design and focus of future studies.\u003c/p\u003e\n\u003cp\u003eFurthermore, clearly defining outcomes and systematically identifying and accounting for confounding factors will contribute to improving the quality and applicability of future research on this topic.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eAI \u0026ndash; anal incontinence \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eCI - confidence interval\u003c/p\u003e\n\u003cp\u003eFI \u0026ndash; fecal incontinence\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eGRADE -\u0026nbsp;Grading of Recommendations Assessment, Development and Evaluation\u003c/p\u003e\n\u003cp\u003eLE \u0026ndash; lateral episiotomy\u0026nbsp;\u003c/p\u003e\n\u003cp\u003emeSH \u0026ndash; medical subject headings\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMLE \u0026ndash; mediolateral episiotomy\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNNT \u0026ndash; number needed to treat\u003c/p\u003e\n\u003cp\u003eOASIS \u0026ndash; obstetric anal sphincter injuries\u003c/p\u003e\n\u003cp\u003eOR \u0026ndash; odds ratio\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePICO - Population, Intervention, Comparison, and Outcome\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePRISMA \u0026ndash; Preferred Reporting Items for Systematic Reviews and Meta-Analyses\u003c/p\u003e\n\u003cp\u003eRCT \u0026ndash; randomized controlled trial\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eROB-2 -\u0026nbsp;risk-of-bias tool\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eROBINS -\u0026nbsp;Risk of Bias in Non- randomized Studies-of Interventions\u003c/p\u003e\n\u003cp\u003eRR- relative risk\u003c/p\u003e\n\u003cp\u003eSD - standard deviation\u003c/p\u003e\n\u003cp\u003eVE \u0026ndash; vacuum extraction\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWHO \u0026ndash; World Health Organisation\u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eEthics approval and consent to participate not required for a literature review.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eConsent for publication: not applicable.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAvailability of data and materials: The datasets used and/or analysed during the current study are available from the corresponding author\u0026nbsp;on reasonable request.\u003c/p\u003e\n\u003cp\u003eCompeting interests: The authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003eFunding: No funding.\u003c/p\u003e\n\u003cp\u003eAuthors' contributions: \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMonika Zinkeviciute, Océane Pécheux: conception,\u0026nbsp;design of the work; have drafted and revised the protocol.\u003c/p\u003e\n\u003cp\u003eAurore Fehlmann, Caroline Daelemans: conception, design of the work; have substantively revised the protocol; will substantively revise the manuscript. Caroline Daelemans is the guarantor of the review.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNicolas Silvestrini: have substantively revised the protocol (statistics and methodology).\u003c/p\u003e\n\u003cp\u003eSophie Gallot: search strategy.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eBegoña Martinez de Tejada: design of the work and revised the protocol.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eUse of artificial intelligence tools:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSome sections of this manuscript were edited with the assistance of AI-based language tools, including ChatGPT (OpenAI) and DeepL Translator, to improve clarity and language fluency. All content was subsequently reviewed and verified by the authors.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eDoumouchtsis SK, De Tayrac R, Lee J, Daly O, Melendez-Munoz J, Lindo FM, et al. An International Continence Society (ICS)/ International Urogynecological Association (IUGA) joint report on the terminology for the assessment and management of obstetric pelvic floor disorders. Int Urogynecology J. 2023 Jan;34(1):1\u0026ndash;42. \u003c/li\u003e\n\u003cli\u003eNilsson IEK, \u0026Aring;kervall S, Molin M, Milsom I, Gyhagen M. Severity and impact of accidental bowel leakage two decades after no, one, or two sphincter injuries. Am J Obstet Gynecol. 2023 Apr;228(4):447.e1-447.e19. \u003c/li\u003e\n\u003cli\u003eOlsson F, Berter\u0026ouml; C. Living with faecal incontinence: trying to control the daily life that is out of control. J Clin Nurs. 2015 Jan;24(1\u0026ndash;2):141\u0026ndash;50. \u003c/li\u003e\n\u003cli\u003eFritel X, Gachon B, Saurel‐Cubizolles M, the EDEN Mother\u0026ndash;Child Cohort Study Group. Postpartum psychological distress associated with anal incontinence in the EDEN mother\u0026ndash;child cohort. BJOG Int J Obstet Gynaecol. 2020 Apr;127(5):619\u0026ndash;27. \u003c/li\u003e\n\u003cli\u003eSideris M, McCaughey T, Hanrahan JG, Arroyo-Manzano D, Zamora J, Jha S, et al. Risk of obstetric anal sphincter injuries (OASIS) and anal incontinence: A meta-analysis. Eur J Obstet Gynecol Reprod Biol. 2020 Sep;252:303\u0026ndash;12. \u003c/li\u003e\n\u003cli\u003eFernando RJ, Sultan AHH, Kettle C, Thakar R, Radley S. Methods of repair for obstetric anal sphincter injury. In: The Cochrane Collaboration, editor. Cochrane Database of Systematic Reviews [Internet]. Chichester, UK: John Wiley \u0026amp; Sons, Ltd; 2006 [cited 2023 Feb 5]. p. CD002866.pub2. Available from: https://doi.wiley.com/10.1002/14651858.CD002866.pub2\u003c/li\u003e\n\u003cli\u003eSultan AH, Monga A, Lee J, Emmanuel A, Norton C, Santoro G, et al. An International Urogynecological Association (IUGA)/International Continence Society (ICS) joint report on the terminology for female anorectal dysfunction. Int Urogynecology J. 2017 Jan;28(1):5\u0026ndash;31. \u003c/li\u003e\n\u003cli\u003eBergendahl S, Ankarcrona V, Leijonhufvud A, Hesselman S, Karlstrom S, Kopp Kallner H, et al. Lateral episiotomy versus no episiotomy to reduce obstetric anal sphincter injury in vacuum-assisted delivery in nulliparous women: study protocol on a randomised controlled trial. BMJ Open. 2019;9(3):e025050. \u003c/li\u003e\n\u003cli\u003eVerghese TS, Champaneria R, Kapoor DS, Latthe PM. Obstetric anal sphincter injuries after episiotomy: systematic review and meta-analysis. Int Urogynecology J. 2016;27(10):1459\u0026ndash;67. \u003c/li\u003e\n\u003cli\u003eBarjon K, Mahdy H. Episiotomy [Internet]. StatPearls [Internet]. StatPearls Publishing; 2022 [cited 2023 Feb 19]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK546675/\u003c/li\u003e\n\u003cli\u003eJiang H, Qian X, Carroli G, Garner P. Selective versus routine use of episiotomy for vaginal birth. Cochrane Database Syst Rev [Internet]. 2017 [cited 2023 May 15];(2). Available from: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD000081.pub3/full\u003c/li\u003e\n\u003cli\u003eUbom AE, Barnea ER, DiSimone N, Mueller M, Beyeza-Kashesya J, Nunes I, et al. FIGO good practice recommendations: Assisted vaginal birth and the second stage of labor. Int J Gynaecol Obstet Off Organ Int Fed Gynaecol Obstet. 2025 Sep 25; \u003c/li\u003e\n\u003cli\u003eKlokk R, Bakken KS, Markestad T, Holten-Andersen MN. Modifiable and non-modifiable risk factors for obstetric anal sphincter injury in a Norwegian Region: a case-control study. BMC Pregnancy Childbirth. 2022;22(1):277. \u003c/li\u003e\n\u003cli\u003ePergialiotis V, Bellos I, Fanaki M, Vrachnis N, Doumouchtsis SK. Risk factors for severe perineal trauma during childbirth: An updated meta-analysis. Eur J Obstet Gynecol Reprod Biol. 2020 Apr;247:94\u0026ndash;100. \u003c/li\u003e\n\u003cli\u003eSegal D, Baumfeld Y, Yahav L, Yohay D, Geva Y, Press F, et al. Risk factors for obstetric anal sphincter injuries (OASIS) during vacuum extraction delivery in a university affiliated maternity hospital. J Matern Fetal Neonatal Med. 2020 Mar 18;33(6):999\u0026ndash;1003. \u003c/li\u003e\n\u003cli\u003eLund NS, Persson LKG, Jang\u0026ouml; H, Gommesen D, Westergaard HB. Episiotomy in vacuum-assisted delivery affects the risk of obstetric anal sphincter injury: a systematic review and meta-analysis. Eur J Obstet Gynecol Reprod Biol. 2016 Dec;207:193\u0026ndash;9. \u003c/li\u003e\n\u003cli\u003eOkeahialam NA, Wong KW, Jha S, Sultan AH, Thakar R. Mediolateral/lateral episiotomy with operative vaginal delivery and the risk reduction of obstetric anal sphincter injury (OASI): A systematic review and meta-analysis. Int Urogynecology J. 2022 Jun;33(6):1393\u0026ndash;405. \u003c/li\u003e\n\u003cli\u003eMack I, Hahn H, G\u0026ouml;del C, Enck P, Bharucha AE. Global Prevalence of Fecal Incontinence in Community-Dwelling Adults: A Systematic Review and Meta-analysis. Clin Gastroenterol Hepatol Off Clin Pract J Am Gastroenterol Assoc. 2024 Apr;22(4):712-731.e8. \u003c/li\u003e\n\u003cli\u003eMaeda K, Koide Y, Katsuno H, Hanai T, Masumori K, Matsuoka H, et al. Prevalence and Risk Factors of Anal and Fecal Incontinence in Japanese Medical Personnel. J Anus Rectum Colon. 2021;5(4):386\u0026ndash;94. \u003c/li\u003e\n\u003cli\u003eBharucha AE, Zinsmeister AR, Locke GR, Seide BM, McKeon K, Schleck CD, et al. Risk factors for fecal incontinence: a population-based study in women. Am J Gastroenterol. 2006 Jun;101(6):1305\u0026ndash;12. \u003c/li\u003e\n\u003cli\u003eGeynisman-Tan J, Kenton K, Leader-Cramer A, Dave B, Bochenska K, Mueller M, et al. Anal Penetrative Intercourse as a Risk Factor for Fecal Incontinence. Female Pelvic Med Reconstr Surg. 2018;24(3):252\u0026ndash;5. \u003c/li\u003e\n\u003cli\u003eShamseer L, Moher D, Clarke M, Ghersi D, Liberati A, Petticrew M, et al. Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015: elaboration and explanation. 2015 Jan 2 [cited 2025 Jul 25]; Available from: https://www.bmj.com/content/349/bmj.g7647\u003c/li\u003e\n\u003cli\u003ePRISMA statement [Internet]. [cited 2025 Aug 22]. PRISMA 2020 flow diagram. Available from: https://www.prisma-statement.org/prisma-2020-flow-diagram\u003c/li\u003e\n\u003cli\u003eSterne JAC, Savović J, Page MJ, Elbers RG, Blencowe NS, Boutron I, et al. RoB 2: a revised tool for assessing risk of bias in randomised trials. BMJ. 2019 Aug 28;l4898. \u003c/li\u003e\n\u003cli\u003eSterne JA, Hern\u0026aacute;n MA, Reeves BC, Savović J, Berkman ND, Viswanathan M, et al. ROBINS-I: a tool for assessing risk of bias in non-randomised studies of interventions. BMJ. 2016 Oct 12;i4919. \u003c/li\u003e\n\u003cli\u003eGRADE Book [Internet]. [cited 2025 Jul 4]. Available from: https://book.gradepro.org/\u003c/li\u003e\n\u003cli\u003eTypes of female genital mutilation [Internet]. [cited 2025 Jul 2]. Available from: https://www.who.int/teams/sexual-and-reproductive-health-and-research-(srh)/areas-of-work/female-genital-mutilation/types-of-female-genital-mutilation\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003e\u003cstrong\u003eTable 1 Key words, MeSH terms and Emtree terms\u003c/strong\u003e \u003cstrong\u003eused for the systematic literature review\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"600\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eConcept 1: primiparous women undergoing an operative vaginal delivery\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eConcept 2: mediolateral or lateral episiotomy\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eConcept 3: anal incontinence\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eControlled vocabulary\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eControlled vocabulary\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eControlled vocabulary\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eEmtree\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eEmtree\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eEmtree\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003e\u0026apos;assisted vaginal delivery\u0026apos;/exp\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u0026apos;episiotomy\u0026apos;/exp\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u0026apos;feces incontinence\u0026apos;/exp\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003e\u0026apos;instrumental delivery\u0026apos;/exp\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u0026apos;lateral episiotomy\u0026apos;/exp\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eflatus incontinence\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003e\u0026apos;obstetric forceps\u0026apos;/exp\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u0026apos;mediolateral episiotomy\u0026apos;/exp\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003e\u0026apos;operative vaginal delivery\u0026apos;/exp\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eControlled vocabulary\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eControlled vocabulary\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eControlled vocabulary\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMeSH\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMeSH\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMeSH\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003e\u0026quot;Extraction, Obstetrical\u0026quot;[Mesh]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u0026quot;Episiotomy\u0026quot;[Mesh]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u0026quot;Fecal Incontinence\u0026quot;[Mesh]\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003e\u0026quot;Obstetrical Forceps\u0026quot;[Mesh]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFree text\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFree text\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFree text\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eKeywords\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eKeywords\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eKeywords\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003e(kiwi NEXT/2 (vacuum OR cup*))\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003elateral episiotom*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e((anal OR anus OR f$ecal OR feces OR stool OR bowel OR rect*) NEXT/1 (incontinence* OR continence*))\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eassisted deliver*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003emediolateral episiotom*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eCleveland Clinic score*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eforceps\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eSt-Mark* NEXT/2 score*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003einstrument* deliver*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003evaizey score*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003emetallic cup*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eomnicup*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003eoperative deliver*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003espatula*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 198px;\"\u003e\n \u003cp\u003evacuum\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eData collection \u0026ndash; characteristics\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"595\" class=\"fr-table-selection-hover\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStudy characteristics\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 259px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePatient characteristics\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 39px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eThe intervention (episiotomy)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eOperative delivery\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003eTitle\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eStudy design\u003c/p\u003e\n \u003cp\u003eStudy duration\u003c/p\u003e\n \u003cp\u003eSample size\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eInclusion and exclusion criteria\u003c/p\u003e\n \u003cp\u003eAuthors and year \u0026nbsp;\u003c/p\u003e\n \u003cp\u003eStudy country\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 259px;\"\u003e\n \u003cp\u003eBody mass index or weight and height\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eEthnicity\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eAge\u003c/p\u003e\n \u003cp\u003eGestational age in weeks\u003c/p\u003e\n \u003cp\u003eNumber of fetuses\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eMedical history of: Crohn\u0026rsquo;s disease or ulcerative colitis, pelvic chemotherapy, pre-existing chronic diarrhea or rectal urgency, Ehlers-Danlos syndrome, presence of any other perianal lesion (perianal fissure, or anorectal or rectovaginal fistula)\u003c/p\u003e\n \u003cp\u003eFemale genital mutilation - defined as any procedure involving partial or total removal of the external female genitalia without medical indication. Classified in according to the WHO (World Health Organisation) female genital mutilation classification (27) \u0026nbsp;\u003c/p\u003e\n \u003cp\u003ePerineal body length\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eOASIS\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eFetal weight\u003c/p\u003e\n \u003cp\u003eFetal presentation: breech or cephalic (occiput anterior or posterior)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 39px;\"\u003e\n \u003cp\u003eMLE or LE\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eAngle and length of episiotomy (incision)\u003c/p\u003e\n \u003cp\u003eAngle and length of episiotomy (suture)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003eType of instrument used \u0026ndash; spatula, forceps (rotational versus non-rotational) and if possible, their type (Kielland, Pageot, Naegele, Tarnier, Piper, Suzor, etc) ventouse (metallic or plastic cup)\u003c/p\u003e\n \u003cp\u003eOperator\u0026rsquo;s experience\u0026nbsp;(years)\u003c/p\u003e\n \u003cp\u003eDuration of the second phase of labor (total duration and specific duration of active pushing phase)\u003c/p\u003e\n \u003cp\u003eEpidural\u003c/p\u003e\n \u003cp\u003eUse of oxytocin during labour\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"systematic-reviews","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sysr","sideBox":"Learn more about [Systematic Reviews](http://systematicreviewsjournal.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/sysr/default.aspx","title":"Systematic Reviews","twitterHandle":"@MedicalEvidence","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"primiparous, episiotomy, anal incontinence, instrumental delivery, obstetric anal sphincter injuries ","lastPublishedDoi":"10.21203/rs.3.rs-8039598/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8039598/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground: \u003c/strong\u003eObstetric anal sphincter injuries are the leading cause of anal incontinence. Primiparous women undergoing assisted vaginal deliveries are at the greatest risk of experiencing these injuries. Mediolateral or lateral episiotomy has been identified as a potential intervention to reduce this risk. However, anal incontinence, the more clinically significant outcome, requires further exploration. The aim of this systematic review is to evaluate whether mediolateral/lateral episiotomy in primiparous women undergoing assisted vaginal delivery reduces the incidence of anal incontinence, and to determine the corresponding number-needed-to-treat (NNT).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods: \u003c/strong\u003eA systematic search of the literature will be conducted in the following information sources: PubMed, The Cochrane Library, EMBASE, Google Scholar and the references list of eligible articles. Articles will be screened against the inclusion and exclusion criteria at the level of the title, abstract and full text. Full-text articles that meet the inclusion criteria will then be assessed independently by two investigators. A sensitivity analyses will be performed. If enough studies report relevant data and the heterogeneity index (I²) is \u0026lt;75%, a meta-analysis will be conducted; otherwise, only a descriptive synthesis will be provided. Risk of bias will be assessed using validated tools, and the overall quality of evidence will be evaluated.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePROSPERO registration number: \u003c/strong\u003e\u0026nbsp;CRD420251076735\u003c/p\u003e","manuscriptTitle":"Does mediolateral or lateral episiotomy reduce the risk of anal incontinence in primiparous women undergoing an operative vaginal delivery? A systematic review and meta-analysis protocol","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-18 18:36:50","doi":"10.21203/rs.3.rs-8039598/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewersInvited","content":"","date":"2025-12-16T10:00:06+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-11-11T06:30:52+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-11-11T06:28:34+00:00","index":"","fulltext":""},{"type":"submitted","content":"Systematic Reviews","date":"2025-11-05T14:37:28+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"systematic-reviews","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sysr","sideBox":"Learn more about [Systematic Reviews](http://systematicreviewsjournal.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/sysr/default.aspx","title":"Systematic Reviews","twitterHandle":"@MedicalEvidence","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"dc797f35-700a-4b24-91fb-4055f91300a8","owner":[],"postedDate":"December 18th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-12-18T18:36:50+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-18 18:36:50","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8039598","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8039598","identity":"rs-8039598","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}