{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T11:45:40Z","timestamp":1791805540571,"version":"4.3.4"},"reference-count":18,"publisher":"FapUNIFESP (SciELO)","issue":"10","license":[{"start":{"date-parts":[[2026,1,1]],"date-time":"2026-01-01T00:00:00Z","timestamp":1767225600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,1,1]],"date-time":"2026-01-01T00:00:00Z","timestamp":1767225600000},"content-version":"am","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,1,1]],"date-time":"2026-01-01T00:00:00Z","timestamp":1767225600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Rev. Assoc. Med. Bras."],"abstract":"<jats:p>SUMMARY  OBJECTIVE: The aim of this study was to evaluate the relationship between intrapartum rectovaginal distance measured by transperineal ultrasonography and obstetric anal sphincter injury severity and second-stage labor duration in nulliparous women undergoing vaginal delivery.  METHODS: This prospective cohort study was conducted at a tertiary referral center in Istanbul, between September 2021 and January 2022. Of 200 consecutive nulliparous women with singleton pregnancies at \u226537 weeks\u2019 gestation, 148 who underwent vaginal delivery were included in the primary analysis. Intrapartum rectovaginal distance was measured in the midsagittal plane by 2D transperineal ultrasonography using a single operator during the inter-contraction rest period, at a fetal head station ranging from -1 to +1. Angle of progression and levator ani anteroposterior diameter were also recorded. Obstetric injury was graded per American College of Obstetricians and Gynecologists 2016 criteria; grade 3\u20134 laceration (severe obstetric anal sphincter injury) was the primary outcome.  RESULTS: Severe obstetric anal sphincter injury occurred in 18 vaginal deliveries (12.2%). Rectovaginal distance was significantly shorter in women with severe obstetric anal sphincter injury (6.91\u00b11.33 mm vs. 9.94\u00b12.75 mm, p&lt;0.001). Second-stage duration was longer with severe obstetric anal sphincter injury (125.8\u00b16.5 vs. 91.3\u00b118.0 min, p&lt;0.001). Receiver operating characteristic analysis identified an rectovaginal distance cut-off of 8.1 mm (AUC=0.846; sensitivity 88.9%, specificity 80.8%). On multivariate logistic regression, rectovaginal distance (OR 0.516, 95%CI 0.373\u20130.713) and body mass index (OR 1.280, 95%CI 1.078\u20131.521) were independently associated with severe obstetric anal sphincter injury.  CONCLUSION: Intrapartum rectovaginal distance measurement by transperineal ultrasonography is a noninvasive, readily obtainable parameter that independently predicts severe obstetric anal sphincter injury and may support individualized intrapartum risk stratification. Multicenter validation with larger samples is warranted.<\/jats:p>","DOI":"10.1590\/1806-9282.20260531","type":"journal-article","created":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T10:57:20Z","timestamp":1791802640000},"source":"Crossref","is-referenced-by-count":0,"title":["Intrapartum rectovaginal distance as a predictor of obstetric anal sphincter injury: a prospective cohort study"],"prefix":"10.1590","volume":"72","author":[{"ORCID":"https:\/\/orcid.org\/0009-0005-1648-2176","authenticated-orcid":false,"given":"Elif G\u00f6rkem","family":"Bademci","sequence":"first","affiliation":[{"name":"Sancaktepe Sehit Prof. Dr. Ilhan Varank Training and Research Hospital","place":["Istanbul, Turkey"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8124-6245","authenticated-orcid":false,"given":"Ya\u011fmur \u015eim\u015fek","family":"Erdim","sequence":"additional","affiliation":[{"name":"Sisli Hamidiye Etfal Training and Research Hospital","place":["Istanbul, Turkey"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7089-3639","authenticated-orcid":false,"given":"Ecem Y\u00fcksel","family":"\u00d6zsoy","sequence":"additional","affiliation":[{"name":"Dar\u0131ca Farabi Training and Research Hospital","place":["Kocaeli, Turkey"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9792-6592","authenticated-orcid":false,"given":"Erkan","family":"El\u00e7i","sequence":"additional","affiliation":[{"name":"Medicana Atakoy Hospital","place":["Istanbul, Turkey"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"530","published-online":{"date-parts":[[2026]]},"reference":[{"key":"ref1","doi-asserted-by":"crossref","first-page":"227","DOI":"10.1111\/codi.16831","article-title":"A systematic review and a meta-analysis on the incidence of obstetric anal sphincter injuries during vaginal 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JOL","year":"2024","journal-title":"Am J Obstet Gynecol"},{"key":"ref5","doi-asserted-by":"crossref","first-page":"486","DOI":"10.1002\/uog.26292","article-title":"Predictive factors for obstetric anal sphincter injury in primiparous women: systematic review and meta-analysis","volume":"62","author":"Packet B","year":"2023","journal-title":"Ultrasound Obstet Gynecol"},{"key":"ref6","doi-asserted-by":"crossref","first-page":"326","DOI":"10.1002\/uog.6294","article-title":"Transperineal ultrasound imaging in prolonged second stage of labor with occipitoanterior presenting fetuses: how well does the \u2018angle of progression\u2019 predict the mode of delivery?","volume":"33","author":"Kalache KD","year":"2009","journal-title":"Ultrasound Obstet Gynecol"},{"key":"ref7","doi-asserted-by":"crossref","first-page":"939","DOI":"10.1007\/s00192-018-3838-5","article-title":"Anovaginal distance and obstetric anal sphincter injury: a prospective observational study","volume":"30","author":"Pihl 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