OBJECTIVES: To assess the feasibility of acquiring adequate transperineal ultrasound (TPUS) volumes of the anal sphincter (AS) immediately after vaginal birth, the reproducibility of its measurements, and detecting defects therein. METHODS: Secondary analysis of TPUS volumes of the AS, acquired immediately after vaginal birth with a transversely oriented convex probe. Two independent experts ranked off-line image quality as "inadequate," "adequate," or "ideal" using the Point-of-Care Ultrasound Image Quality scale. On "adequate" and "ideal" quality volumes, the length of the external AS at 6 and 12 o'clock, and the volume of the external and internal AS were measured. Additionally, volumes were screened for AS defects on tomographic ultrasound imaging. Subsequently, we rated the intra- and interrater agreement on those findings. RESULTS: Of 183 volumes, 162 were considered "adequate" or of "ideal" quality (88.5%). Reasons for "inadequacy" were shadow artifacts (16/21), poor resolution (3/21), incomplete acquisition (1/21), or aberrant AS morphology (1/21). The intrarater reliability of two-dimensional (2D) and three-dimensional (3D) measurements was excellent, whereas interrater reliability was fair to good for 2D measurements and good for 3D measurements. In those tomographic ultrasound imaging (TUI) sequences including AS defects, the intra- and interrater reliability of the defect measurement were excellent [intraclass correlation coefficient (ICC) = 0.92 (0.80-0.94)] and moderate [ICC = 0.72 (0.63-0.79)]. In this cohort, there were only few (4/48; 8.3%) AS defects. However, grading them was poorly reproducible between experts. CONCLUSION: TPUS of the AS immediately after vaginal birth yields adequate image quality and allows for reproducible measurements. In the few patients with AS defects, there was good agreement on the presence, but it was poor for the extent of defects.

3rd Faculty of Medicine Institute for the Care of Mother and Child Charles University Prague Czech Republic

Department of Development and Regeneration Cluster Urogenital Surgery Biomedical Sciences KU Leuven Leuven Belgium

Department of Gynaecology and Obstetrics UZ Leuven Leuven Belgium

Research Department of Maternal Fetal Medicine Institute for Women's Health University College London London UK

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Hoyte L, Damaser MS, Warfield SK, et al. Quantity and distribution of levator ani stretch during simulated vaginal childbirth. Am J Obstet Gynecol 2008; 199:198.e1–198.e5.

Lien KC, Morgan DM, Delancey JO, Ashton‐Miller JA. Pudendal nerve stretch during vaginal birth: a 3D computer simulation. Am J Obstet Gynecol 2005; 192:1669–1676.

Smith LA, Price N, Simonite V, Burns EE. Incidence of and risk factors for perineal trauma: a prospective observational study. BMC Pregnancy Childbirth 2013; 13:59.

Caudwell‐Hall J, Kamisan Atan I, Guzman Rojas R, Langer S, Shek KL, Dietz HP. Atraumatic normal vaginal delivery: how many women get what they want? Am J Obstet Gynecol 2018; 219:379.e1–379.e8.

Fernando RJ, Sultan AH, Freeman RM, Williams AA, Adams EJ. The Management of Third‐ and Fourth‐Degree Perineal Tears. Green‐top Guideline No 29. RCOG; 2015.

Doumouchtsis SK, de Tayrac R, Lee J, 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 Urogynecol J 2022; 34:1–42.

Keighley MR, Perston Y, Bradshaw E, Hayes J, Keighley DM, Webb S. The social, psychological, emotional morbidity and adjustment techniques for women with anal incontinence following obstetric anal sphincter injury: use of a word picture to identify a hidden syndrome. BMC Pregnancy Childbirth 2016; 16:275.

Evans E, Falivene C, Briffa K, Thompson J, Henry A. What is the total impact of an obstetric anal sphincter injury? An Australian retrospective study. Int Urogynecol J 2020; 31:557–566.

Visscher AP, Lam TJ, Hart N, Felt‐Bersma RJ. Fecal incontinence, sexual complaints, and anorectal function after third‐degree obstetric anal sphincter injury (OASI): 5‐year follow‐up. Int Urogynecol J 2014; 25:607–613.

Desseauve D, Proust S, Carlier‐Guerin C, Rutten C, Pierre F, Fritel X. Evaluation of long‐term pelvic floor symptoms after an obstetric anal sphincter injury (OASI) at least one year after delivery: a retrospective cohort study of 159 cases. Gynecol Obstet Fertil 2016; 44:385–390.

Sideris M, McCaughey T, Hanrahan JG, et al. Risk of obstetric anal sphincter injuries (OASIS) and anal incontinence: a meta‐analysis. Eur J Obstet Gynecol Reprod Biol 2020; 252:303–312.

Walsh KA, Grivell RM. Use of endoanal ultrasound for reducing the risk of complications related to anal sphincter injury after vaginal birth. Cochrane Database Syst Rev 2015; 2015:CD010826.

Faltin DL, Boulvain M, Irion O, Bretones S, Stan C, Weil A. Diagnosis of anal sphincter tears by postpartum endosonography to predict fecal incontinence. Obstet Gynecol 2000; 95:643–647.

Huber M, Larsson C, Harrysson M, et al. Use of endoanal ultrasound in detecting obstetric anal sphincter injury immediately after birth. Acta Obstet Gynecol Scand 2023; 102:389–395.

Sandridge AD, Thorp MJ. Vaginal endosonography in the assessment of the anorectum. Obstet Gynecol 1995; 86:1007–1009.

Peschers UM, DeLancey JOL, Schaer GN, Schuessler B. Exoanal ultrasound of the anal sphincter: normal anatomy and sphincter defects. BJOG Int J Obstet Gynaecol 1997; 104:999–1003.

Timor‐Tritsch IE, Monteagudo A, Smilen SW, Porges RF, Avizova E. Simple ultrasound evaluation of the anal sphincter in female patients using a transvaginal transducer. Ultrasound Obstet Gynecol 2005; 25:177–183.

Hall RJ, Rogers RG, Saiz L, Qualls C. Translabial ultrasound assessment of the anal sphincter complex: normal measurements of the internal and external anal sphincters at the proximal, mid‐, and distal levels. Int Urogynecol J Pelvic Floor Dysfunct 2007; 18:881–888.

Cattani L, van Schoubroeck D, Housmans S, et al. Exo‐anal imaging of the anal sphincter: a comparison between introital and transperineal image acquisition. Int Urogynecol J 2020; 31:1107–1113.

Ros C, Martínez‐Franco E, Wozniak MM, et al. Postpartum two‐ and three‐dimensional ultrasound evaluation of anal sphincter complex in women with obstetric anal sphincter injury. Ultrasound Obstet Gynecol 2017; 49:508–514.

AIUM/IUGA practice parameter for the performance of Urogynecological ultrasound examinations. Int Urogynecol J 2019; 30:1389–1400.

Stuart A, Ignell C, Örnö AK. Comparison of transperineal and endoanal ultrasound in detecting residual obstetric anal sphincter injury. Acta Obstet Gynecol Scand 2019; 98:1624–1631.

Taithongchai A, van Gruting IMA, Volløyhaug I, Arendsen LP, Sultan AH, Thakar R. Comparing the diagnostic accuracy of 3 ultrasound modalities for diagnosing obstetric anal sphincter injuries. Am J Obstet Gynecol 2019; 221:134.e1–134.e9.

Lee JH, Pretorius DH, Weinstein M, Guaderrama NM, Nager CW, Mittal RK. Transperineal three‐dimensional ultrasound in evaluating anal sphincter muscles. Ultrasound Obstet Gynecol 2007; 30:201–209.

Valsky DV, Messing B, Petkova R, et al. Postpartum evaluation of the anal sphincter by transperineal three‐dimensional ultrasound in primiparous women after vaginal delivery and following surgical repair of third‐degree tears by the overlapping technique. Ultrasound Obstet Gynecol 2007; 29:195–204.

Weinstein MM, Pretorius DH, Jung SA, Nager CW, Mittal RK. Transperineal three‐dimensional ultrasound imaging for detection of anatomic defects in the anal sphincter complex muscles. Clin Gastroenterol Hepatol 2009; 7:205–211.

Oom JDM, West LR, Schouten RW, Steensma BA. Detection of anal sphincter defects in female patients with fecal incontinence: a comparison of 3‐dimensional transperineal ultrasound and 2‐dimensional endoanal ultrasound. Dis Colon Rectum 2012; 55:646–652.

Shek KL, Guzman‐Rojas R, Dietz HP. Residual defects of the external anal sphincter following primary repair: an observational study using transperineal ultrasound. Ultrasound Obstet Gynecol 2014; 44:704–709.

Guzman Rojas RA, Kamisan Atan I, Shek KL, Dietz HP. Anal sphincter trauma and anal incontinence in urogynecological patients. Ultrasound Obstet Gynecol 2015; 46:363–366.

Wong KW, Thakar R, Andrews V, Sultan AH. Is there a role for transperineal ultrasound imaging of the anal sphincter immediately after primary repair of third degree tears? Eur J Obstet Gynecol Reprod Biol 2022; 271:260–264.

Dessie AS, Calhoun AW, Kanjanauptom P, et al. Development and validation of a point‐of‐care‐ultrasound image quality assessment tool: the POCUS IQ scale. J Ultrasound Med 2023; 42:135–145.

Mokkink LB, de Vet H, Diemeer S, Eekhout I. Sample size recommendations for studies on reliability and measurement error: an online application based on simulation studies. Health Serv Outcome Res Methodol 2023; 23:241–265.

Dietz HP. Exoanal imaging of the anal sphincters. J Ultrasound Med 2018; 37:263–280.

Magpoc Mendoza J, Turel Fatakia F, Kamisan Atan I, Dietz HP. Normal values of anal sphincter biometry by 4‐dimensional translabial ultrasound: a retrospective study of pregnant women in their third trimester. J Ultrasound Med 2019; 38:2733–2738.

Starck M, Bohe M, Valentin L. Results of endosonographic imaging of the anal sphincter 2‐7 days after primary repair of third‐ or fourth‐degree obstetric sphincter tears. Ultrasound Obstet Gynecol 2003; 22:609–615.

Subramaniam N, Dietz HP. What is a significant defect of the anal sphincter on translabial ultrasound? Ultrasound Obstet Gynecol 2020; 55:411–415.

Subramaniam N, Dietz HP. Does exclusion of subcutaneous external anal sphincter on exoanal imaging matter? Ultrasound Obstet Gynecol 2020; 55:830–834.

Turel FD, Langer S, Shek KL, Dietz HP. Medium‐ to long‐term follow‐up of obstetric anal sphincter injury. Dis Colon Rectum 2019; 62:348–356.

Bravo‐Valenzuela NJ, Peixoto AB, Mattar R, Melo Júnior JF, da Silva Pares DB, Araujo JE. Fetal cardiac function and ventricular volumes determined by three‐dimensional ultrasound using STIC and VOCAL methods in fetuses from pre‐gestational diabetic women. Pediatr Cardiol 2020; 41:1125–1134.

Cicchetti D. Guidelines, criteria, and rules of thumb for evaluating normed and standardized assessment instruments in psychology. Psychol Assess 1994; 6:284–290.

Altman DG. Practical Statistics for Medical Research. Boca Raton: CRC Press; 1991.

Subramaniam N, Robledo KP, Dietz HP. Anal sphincter imaging: better done at rest or on pelvic floor muscle contraction? Int Urogynecol J 2020; 31:1191–1196.

Bellussi F, Montaguti E, Youssef A, Salsi G, Ghi T, Pilu G. Dynamic 2‐dimensional transperineal ultrasound evaluation in labor room as a screening tool for anal sphincter injuries and anal incontinence in primiparous women. Am J Obstet Gynecol MFM 2019; 1:100037.

Andrews V, Sultan AH, Thakar R, Jones PW. Occult anal sphincter injuries—myth or reality? BJOG 2006; 113:195–200.

Faltin DL, Boulvain M, Floris LA, Irion O. Diagnosis of anal sphincter tears to prevent fecal incontinence: a randomized controlled trial. Obstet Gynecol 2005; 106:6–13.

Wong KW, Thakar R, Sultan AH, Andrews V. Can transperineal ultrasound improve the diagnosis of obstetric anal sphincter injuries? Int Urogynecol J 2022; 33:2809–2814.

Packet B, Page AS, Cattani L, Bosteels J, Deprest J, Richter J. Predictive factors for obstetric anal sphincter injury in primiparous women: systematic review and meta‐analysis. Ultrasound Obstet Gynecol 2023; 62:486–496.