Clinical characteristics and outcomes of anterior anus in female infants: a multicenter retrospective cohort study

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This study evaluated the clinical features, associated anomalies, and outcomes of AA in female infants. Methods: This multicenter retrospective cohort study included infants diagnosed with AA between 2020 and 2024 at six tertiary referral centers in South Korea. The clinical characteristics, coexisting anomalies, and outcomes including constipation and urinary tract infections were analyzed. Results: Among the 64 patients included in this study, 51.6% had a concomitant perineal groove. Congenital heart diseases were the most common coexisting anomaly, occurring in 32 patients. During a mean follow-up of 22.9 months, constipation was observed in 23% of the patients. Urinary tract infections were not observed. The perineal groove resolved spontaneously in 87.9% of cases. Conclusion: AA is a benign anatomical variant that does not increase the risk of constipation or urinary tract infections. Given the observed association with congenital heart disease, cardiac evaluation should be considered when clinically indicated. Anterior anus Anorectal malformation Perineal groove Infants Constipation Urinary tract infection Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Anterior anus (AA), also referred to as “ectopic anus,” “anterior ectopic anus,” or “anterior displacement of the anus,” has traditionally been considered a mild form of anorectal malformation (ARM) [1, 2]. However, the absence of a standardized definition has led to inconsistencies in clinical management. Surgical intervention was historically the standard treatment [3, 4], but recent studies suggest that conservative management is often sufficient, with no significant long-term complications [5-7]. AA is now precisely defined as a normally shaped anus located anterior to its typical position, fully surrounded by the external sphincter muscle, and with a normal anal caliber. These features distinguish AA from true forms of ARM and support its classification as a normal anatomical variant rather than a pathological anomaly. While symptoms such as constipation or lower urinary tract infections (UTIs) have been reported in patients with AA, their prevalence is similar to that of the general pediatric population [7]. Moreover, recent research suggests that AA does not significantly impact gynecological outcomes in post-menarchal women [5]. Despite the establishment of a standardized definition of AA by the 2022 ARM-Net Consortium Consensus [1], its clinical implications remain inadequately explored. Although the association between AA and cardiac, spinal, and renal anomalies – components of the VACTERL association (vertebral, anorectal, cardiac, tracheoesophageal, renal, and limb anomalies) – is unclear, no studies have specifically investigated the necessity of VACTERL screening in patients with AA. This multicenter study aimed to characterize the clinical features and outcomes of AA and to contribute to the development of clearer clinical guidelines and management strategies for affected patients. Methods Ethical considerations The Institutional Review Boards of all participating institutions approved this study (DSMC IRB 2024-12-059). The requirement for informed consent was waived due to the retrospective and non-interventional nature of the study. All patient data were anonymized and de-identified in accordance with institutional privacy regulations. Study design and patient population This multicenter retrospective cohort study investigated the clinical characteristics and outcomes of neonates and infants diagnosed with AA. Patients were enrolled from six tertiary referral centers in South Korea from November 2020 to December 2024. The inclusion criteria were as follows: female infants (aged 0-12 months) who met the diagnostic criteria for AA. The diagnosis was confirmed using the anal position index (API), a quantitative parameter that assesses the anal position relative to the perineal body. According to the ARM-Net Consortium Consensus, an API of < 0.34 in females was considered diagnostic for AA. The exclusion criteria were as follows: patients with other ARMs, particularly perineal fistula; those with incomplete API measurements or insufficient data on sphincter evaluation; and patients lost to follow-up. One male patient was excluded from the analysis as meaningful conclusions could not be drawn from a single case. Measurement of anal caliber and sphincter function Anal caliber was assessed using Hegar dilators. The largest Hegar size that could be inserted without resistance was recorded and compared with age-appropriate reference values to confirm normal caliber [8]. Sphincter function was evaluated through clinical examination. Sphincter muscle integrity was assessed by gently stimulating the perianal skin with a cotton swab to elicit a contraction reflex. Additionally, sphincter tone was subjectively evaluated by observing the constriction around the Hegar dilator during insertion. Electrical stimulation using a muscle-locating stimulator was not performed, as it requires general anesthesia with muscle relaxants and is not feasible in our clinical setting. Only patients with both normal anal caliber and intact sphincter function were included in the study. Measurement of the API To determine the API, the relative position of the anal opening within the perineum was assessed. First introduced by Reisner et al. in 1984 [9], the API is calculated as the ratio of perineal length to posterior pelvic floor length. In female patients, perineal length was measured as the distance from the fourchette to the center of the anus, while the posterior pelvic floor length was defined as the distance from the fourchette to the tip of the coccyx (Fig. 1). All API measurements were performed by pediatric surgeons at each participating center. To minimize interobserver variability, measurement was conducted using standardized anatomical landmarks, and representative images were reviewed in consensus when ambiguity arose. However, inter- and intra-rater reliability was not formally assessed. Representative initial and final follow-up images of patients with AA are presented in Fig. 2. Data collection Clinical and demographic data were collected from the electronic medical records of each participating institution. A standardized case report form was used across all six centers to ensure consistent data acquisition. Information collected included patient demographics, clinical presentation, diagnostic findings, and follow-up outcomes. At the time of initial diagnosis, the following clinical characteristics were recorded: age, gestational age at birth, and birth weight. Diagnostic data included API measurements, sacral ratio determined by pelvic radiography, spinal ultrasonography findings, and transthoracic echocardiography (TTE) results. The presence of congenital anomalies was assessed based on imaging findings and documented medical history. Supplementary clinical data were collected during follow-up period to evaluate patient outcomes. These included changes in API values and the development of constipation, UTIs, or growth failure. UTIs were defined as a history of hospitalization for fever, excluding cases attributable to upper respiratory infections. For patients who underwent surgical intervention, postoperative API values were recorded to assess anatomical changes. Outcome measures The primary objective of this study was to assess the long-term clinical outcomes of patients with AA. Primary endpoints included the incidence of constipation, history of recurrent UTIs, longitudinal changes in the API, and the presence of congenital anomalies. Secondary outcomes included growth failure and the need for surgical intervention. Growth failure was assessed using standardized growth curves and age-appropriate weight percentiles. Surgical interventions were analyzed to evaluate the indications for surgery, types of procedures performed, and postoperative outcomes. Statistical Analysis Descriptive statistics were used to summarize patient characteristics and clinical outcomes. Continuous variables are presented as means ± standard deviations or means with standard error of the mean, and categorical variables are reported as frequencies and percentages. Normality was assessed to evaluate changes in API over time, and Wilcoxon signed-rank tests were used to compare paired API values, as the data were not normally distributed. Paired line plots were generated to visualize individual API variations over time. All statistical analyses were performed using the Statistical Package for the Social Sciences, version 29 (IBM corp., Armonk, NY, USA). A p -value < 0.05 was considered statistically significant. Results Patient characteristics This study included 64 female patients diagnosed with AA. The mean API at the time of diagnosis was 0.31 (Table 1). A perineal groove (PG) was frequently observed as a coexisting finding during clinical evaluation. Among the patients, 33 (51.6%) had coexisting PG, while 31 (48.4%) had AA without PG. Of the 33 patients with PG, 18 (54.5%) were classified as having total PG and 15 (45.4%) as having partial PG [10]. Associated anomalies Congenital anomalies were identified in several patients, with congenital heart disease (CHD) being the most common. Of the 64 patients, 46 underwent TTE, and CHDs were identified in 32 of them. Twenty-six patients had mild CHDs, including atrial septal defect, patent foramen ovale, and patent ductus arteriosus (PDA), which rarely required surgical intervention. Six patients underwent cardiac surgery: two with tetralogy of Fallot, two with atrial septal defect and PDA requiring PDA ligation, and two with atrioventricular septal defects. Among these six patients, three had additional syndromic conditions, including visceral smooth muscle dysfunction syndrome, mosaic Edwards syndrome, and Bardet–Biedl syndrome. Pelvic X-rays were performed in 56 patients, revealing a mean sacral AP ratio of 1.04, with no sacral bone anomalies. Spinal ultrasonography was conducted in 40 patients, all of whom showed no abnormalities. Other congenital anomalies included one case each of Jacobsen syndrome, Pfeiffer syndrome, and polydactyly. Clinical outcomes and follow-up The mean follow-up period was 22.9 months. Constipation occurred in 23% of patients, most of whom responded well to conservative management with intermittent use of laxatives or dietary modifications. No cases of UTI were reported. One patient with mosaic Edwards syndrome exhibited growth failure, which was attributed to the underlying syndrome rather than AA. Analysis of patients who underwent surgery Among the 64 patients, three underwent surgical intervention based on parental concern, despite medical reassurance that surgery was not necessary. The preoperative API values for these three patients were 0.32, 0.30, and 0.31, respectively, and the corresponding postoperative values were 0.33, 0.25, and 0.30. In all three cases, the API remained within the diagnostic range for AA, indicating no significant anatomical correction. Two of the three patients had concurrent PG, which resolved postoperatively (Fig. 3). None of the surgically treated patients experienced constipation or UTIs during follow-up. Comparison of the API over time To evaluate whether the anal position changed over time, initial and last follow-up API values were compared (Fig. 4). The Wilcoxon signed-rank test revealed no statistically significant difference, indicating that the anal position remained unchanged during follow-up period, regardless of growth or surgical intervention. Discussion This is the first multicenter retrospective cohort study to analyze the clinical outcomes of AA. Our findings align with previous studies indicating that AA is a benign anatomical variant with minimal long-term morbidity [5, 7]. Notably, the prevalence of constipation and UTIs in our cohort was not significantly different from that in the general pediatric population. Constipation was observed in 23% of patients and was generally manageable with intermittent laxatives or other conservative treatments. This prevalence is consistent with findings from previous Korean studies [11] and reports from the United Kingdom [6], further supporting the notion AA is not a significant risk factor for constipation. Additionally, no cases of UTIs requiring hospitalization were reported during follow-up, suggesting that AA does not increase the risk of UTIs. The relatively high rate of congenital anomalies was a notable finding, with CHD being the most common. Among the 46 patients who underwent TTE, 32 (69.6%) had CHDs, and 6 (13%) had critical CHDs requiring surgical intervention. Considering that CHD occurs in approximately 1% of the general pediatric population, with 25% of those cases classified as critical, our findings suggest a substantially higher prevalence of CHD in patients with AA [12, 13]. While a recent study from the United Kingdom [6] recommended against routine TTE screening in patients with AA, our results indicate that clinicians should remain vigilant for the possibility of CHD and consider appropriate evaluation when clinically indicated. In this study, 51.6% of patients with AA also had a coexisting PG, suggesting that PG may frequently occur in conjunction with AA. However, to our knowledge, no previous studies have specifically addressed the relationship between AA and PG. The association between these two conditions remains unclear and warrants further large-scale studies to better understand their relationship and clinical implications. PG is a congenital malformation characterized by a mucosa-lined tract extending from the anus toward the posterior fourchette [14]. Although PG is relatively rare, some reports have described its association with local irritation or infection, occasionally leading to surgical intervention [14-16]. In our cohort, however, despite the coexistence of AA and PG, there was no increased risk of infection observed during follow-up. Previous studies [10], have demonstrated that PG typically follows a benign course and resolves spontaneously without the need for surgical intervention in most cases. Although those studies focused on patients with isolated PG, the clinical course in our cohort of patients with AA and coexisting PG was similarly benign. Consistent with prior findings, 87.9% of PG cases in our study resolved spontaneously, supporting the feasibility of conservative management [10, 15-17]. The only notable postoperative change among the three patients who underwent surgery was the resolution of PG in those who initially presented with it; the API remained largely unchanged. These findings suggest that surgical intervention did not significantly alter the position of the anus but may have been effective in resolving coexisting PG. Based on our results, a non-surgical approach may be appropriate for patients with AA and PG due to the absence of significant complications and the tendency for spontaneous resolution. However, the limited number of surgical cases in this study precludes drawing definitive conclusions. Despite the strengths of this study, including its multicenter design and standardized data collection, several limitations should be acknowledged. First, as a retrospective study, there is potential for selection bias in both the initial diagnosis and patient follow-up. A standardized prospective study would allow for a more accurate assessment. Second, a longer follow-up period is necessary to evaluate the functional outcomes of AA into adolescence and adulthood, particularly in patients with or without PG. Conclusion Anterior anus does not appear to increase the risk of constipation or UTIs. PG, when present, showed a high rate of spontaneous resolution, supporting the feasibility of conservative management. Although some patients had congenital anomalies, particularly CHDs, the overall morbidity associated with AA was low. Notably, surgical intervention did not change the anal positioning and was primarily effective only in resolving PG when present. Given the stable long-term outcomes observed in this study, routine surgical correction of AA is generally not necessary. Nonetheless, clinicians should remain vigilant for potential associated anomalies, especially CHD, and consider appropriate screening when clinically indicated. Future prospective studies with longer follow-up are needed to better define the natural history and long-term outcomes of AA. Refining clinical guidelines based on such evidence will help optimize the management of AA, ensuring appropriate and individualized care for affected patients. Declarations Funding: This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. Conflicts of interest: The authors declare no conflicts of interest. Consent to participate: Not applicable. Author contributions: Yong Jae Kwon contributed to study design, data collection, statistical analysis, and manuscript drafting. Eunyoung Jung supervised the study, contributed to interpretation of results, and critically revised the manuscript. Hyunhee Kwon, Suhyeon Ha, and Dae Yeon Kim contributed to patient enrollment and data acquisition. Yu Jeong Cho, Ju Yeon Lee, and So Hyun Nam contributed to clinical data interpretation and manuscript editing. All authors reviewed and approved the final version of the manuscript. Data availability statement: The datasets generated and/or analyzed during the current study are not publicly available due to patient privacy concerns but are available from the corresponding author on reasonable request. References Amerstorfer EE, Schmiedeke E, Samuk I et al (2022) Clinical differentiation between a normal anus, anterior anus, congenital anal stenosis, and perineal fistula: definitions and consequences-the ARM-Net consortium consensus. Children (Basel) 9:831. https://doi.org/10.3390/children9060831 Pakarinen MP, Rintala RJ (2010) Management and outcome of low anorectal malformations. Pediatr Surg Int 26:1057–1063. https://doi.org/10.1007/s00383-010-2697-z Abeyaratne M (1991) Posterior transposition of anterior ectopic anus. J Pediatr Surg 26:725–727. https://doi.org/10.1016/0022-3468(91)90020-t Hendren WH (1978) Constipation caused by anterior location of the anus and its surgical correction. J Pediatr Surg 13:505–512. https://doi.org/10.1016/s0022-3468(78)80315-7 Duci M, Fascetti-Leon F, Bogana G, Gamba P, Midrio P (2021) Conservative management of anterior located anus: a medium-long term follow up. J Pediatr Surg 56:2277–2280. https://doi.org/10.1016/j.jpedsurg.2021.04.003 Hotonu S, Annett A, Campbell A, Bradnock T, Walker G (2025) Outcomes of management of anterior anus in girls in Glasgow, UK. J Pediatr Surg 60:162023. https://doi.org/10.1016/j.jpedsurg.2024.162023 Kyrklund K, Pakarinen MP, Taskinen S, Rintala RJ (2015) Bowel function and lower urinary tract symptoms in females with anterior anus treated conservatively: Controlled outcomes into adulthood. J Pediatr Surg 50:1168–1173. https://doi.org/10.1016/j.jpedsurg.2014.09.074 Holcomb GW, Murphy JP, St. Peter SD (2020) Holcomb and Ashcraft's pediatric surgery. 7th edn. Elsevier, Edinburgh ; New York Reisner SH, Sivan Y, Nitzan M, Merlob P (1984) Determination of anterior displacement of the anus in newborn infants and children. Pediatrics 73:216–217 Ihn K, Na Y, Ho IG, Oh JT (2020) Clinical characteristics and conservative treatment of perineal groove. J Pediatr Surg 55:1507–1510. https://doi.org/10.1016/j.jpedsurg.2019.07.017 Kim HJ, Moon JS, Hwang JH et al (2006) Clinical feature and dietary pattern of infantile constipation under two years of age. Pediatr Gastroenterol Hepatol Nutr 9:31–38 Hoffman JI, Kaplan S (2002) The incidence of congenital heart disease. J Am Coll Cardiol 39:1890–1900. https://doi.org/10.1016/s0735-1097(02)01886-7 Oster ME, Lee KA, Honein MA, Riehle-Colarusso T, Shin M, Correa A (2013) Temporal trends in survival among infants with critical congenital heart defects. Pediatrics 131:e1502–e1508. https://doi.org/10.1542/peds.2012-3435 King SK, Levitt MA (2022) Advances in the management of the neonate born with an anorectal malformation. Clin Perinatol 49:965–979. https://doi.org/10.1016/j.clp.2022.08.002 Garcia-Palacios M, Mendez-Gallart R, Cortizo-Vazquez J, Rodriguez-Barca P, Estevez-Martinez E, Bautista-Casasnovas A (2017) Perineal groove in female infants: a case series and literature review. Pediatr Dermatol 34:677–680. https://doi.org/10.1111/pde.13311 Samuk I, Amerstorfer EE, Fanjul M et al (2020) Perineal groove: an anorectal malformation network, consortium study. J Pediatr 222:207–212. https://doi.org/10.1016/j.jpeds.2020.03.026 Esposito C, Giurin I, Savanelli A, Alicchio F, Settimi A (2011) Current trends in the management of pediatric patients with perineal groove. J Pediatr Adolesc Gynecol 24:263–265. https://doi.org/10.1016/j.jpag.2011.02.011 Table 1 Table 1 Demographics and clinical characteristics of female infants diagnosed with anterior anus ( n = 64) Characteristics Value, n (%) or Mean ± SEM a Gestational age (weeks) 37.5 ± 0.2 Birth weight (g) 2916 ± 70 Anal position index 0.31 ± 0.004 Perineal groove Total Partial 33/64 (51.6) 18/33 (54.5) 15/33 (45.4) Associated anomalies Congenital heart disease (CHD) Mild b Critical c Others d 35/64 (54.7) 32 26 (81.3) 6 (18.8) 5 Follow-up duration (months) 22.8 ± 1.2 a SEM, standard error of the mean b Mild CHD refers to conditions not requiring surgical intervention (e.g., small atrial septal defect, small patent foramen ovale, small patent ductus arteriosus) c Critical CHD refers to conditions requiring surgical intervention or procedures within the first year of life d Other syndromic anomalies include mosaic Edward syndrome, Jacobsen syndrome, Pfeiffer syndrome, Bardet–Biedl syndrome, and visceral smooth muscle dysfunction syndrome Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 16 Sep, 2025 Read the published version in Pediatric Surgery International → Version 1 posted Editorial decision: Revision requested 01 Sep, 2025 Reviews received at journal 26 Aug, 2025 Reviewers agreed at journal 15 Aug, 2025 Reviewers agreed at journal 12 Aug, 2025 Reviewers invited by journal 10 Aug, 2025 Editor assigned by journal 01 Aug, 2025 Submission checks completed at journal 01 Aug, 2025 First submitted to journal 25 Jul, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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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-7212488","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":499567935,"identity":"6163e906-2fd4-4bce-91c2-8aebc29d0a37","order_by":0,"name":"Yong Jae Kwon","email":"","orcid":"","institution":"Gangneung Asan Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yong","middleName":"Jae","lastName":"Kwon","suffix":""},{"id":499567936,"identity":"c52b935c-5e45-417c-91ea-638d12772b44","order_by":1,"name":"Hyunhee Kwon","email":"","orcid":"","institution":"Asan Medical Center Children's Hospital","correspondingAuthor":false,"prefix":"","firstName":"Hyunhee","middleName":"","lastName":"Kwon","suffix":""},{"id":499567937,"identity":"5bbccb38-bf3e-4be8-8dee-e177219b5119","order_by":2,"name":"Suhyeon Ha","email":"","orcid":"","institution":"Asan Medical Center Children's Hospital","correspondingAuthor":false,"prefix":"","firstName":"Suhyeon","middleName":"","lastName":"Ha","suffix":""},{"id":499567938,"identity":"9411e327-9c1f-4c82-b6d1-6ceb7ac872c3","order_by":3,"name":"Dae Yeon Kim","email":"","orcid":"","institution":"Asan Medical Center Children's Hospital","correspondingAuthor":false,"prefix":"","firstName":"Dae","middleName":"Yeon","lastName":"Kim","suffix":""},{"id":499567939,"identity":"3392af61-9a77-4204-a73e-859bc36b1d39","order_by":4,"name":"Yu Jeong Cho","email":"","orcid":"","institution":"Hanyang University Guri Hospital, Hanyang University College of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Yu","middleName":"Jeong","lastName":"Cho","suffix":""},{"id":499567940,"identity":"84421915-1b0a-4a86-8c27-aa89e167d4db","order_by":5,"name":"Ju Yeon Lee","email":"","orcid":"","institution":"Chonnam National University Hospital","correspondingAuthor":false,"prefix":"","firstName":"Ju","middleName":"Yeon","lastName":"Lee","suffix":""},{"id":499567941,"identity":"49f1b640-eb3d-40ac-bc36-b679516fc0af","order_by":6,"name":"So Hyun Nam","email":"","orcid":"","institution":"Inje University Busan Paik Hospital","correspondingAuthor":false,"prefix":"","firstName":"So","middleName":"Hyun","lastName":"Nam","suffix":""},{"id":499567942,"identity":"a37db23e-5154-45af-9d37-7387d3739c84","order_by":7,"name":"Eunyoung Jung","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAw0lEQVRIiWNgGAWjYHCCBCC2MUDiEKcljTQtIHCYBC38EgnPpAt+nTfWnZHA+OEHQ1o+QS2SMxLSpGf23TYzu5HALNnDkGPZQEiLwQ2gFt6e2zZALQzSDAwVBoR0MNhDtJwDaWH+TZQWAwmgFp4fB0AOYwPakkNYi8SZB8nWvA3JxmZnHrZZ9hikEdbC356TeJvnj53htuPJh2/8qEgmrIVBICeBgbENxGJsALqTsAagNccPMDD8IUblKBgFo2AUjFgAAGesOcvTsEUtAAAAAElFTkSuQmCC","orcid":"","institution":"Keimyung University Dongsan Medical Center, Keimyung University School of Medicine","correspondingAuthor":true,"prefix":"","firstName":"Eunyoung","middleName":"","lastName":"Jung","suffix":""}],"badges":[],"createdAt":"2025-07-25 09:08:27","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7212488/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7212488/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00383-025-06196-3","type":"published","date":"2025-09-16T15:57:13+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":89259437,"identity":"adfce791-abfa-4295-9c56-69d84e1e8132","added_by":"auto","created_at":"2025-08-18 06:27:13","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":293898,"visible":true,"origin":"","legend":"\u003cp\u003eAPI measurement in females. The API is calculated as the ratio of the distance between the anal fourchette and coccyx (A/B).\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7212488/v1/3f0a8a8d0eaa55c1f828ee5e.png"},{"id":89260350,"identity":"5200433d-01cc-4103-ab02-a993b1be4548","added_by":"auto","created_at":"2025-08-18 06:43:13","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1163988,"visible":true,"origin":"","legend":"\u003cp\u003ePicture of a patient with anterior anus. The API was 0.23 at the initial visit (A) and 0.27 at the final follow-up (B).\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7212488/v1/6cbf14434e93cd51b729b2b6.png"},{"id":89259441,"identity":"86ddc8b0-e076-49fa-90c7-c35283d0fd6a","added_by":"auto","created_at":"2025-08-18 06:27:13","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":961934,"visible":true,"origin":"","legend":"\u003cp\u003eInitial clinical image of a patient with anterior anus and total perineal groove (A), and image of the postoperative state (B). The API has not changed (0.34 initially and 0.33 postoperatively), and only the perineal groove is removed.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7212488/v1/694197d8a4f1672e8e9cbc89.png"},{"id":89260351,"identity":"b87121ab-1a40-4b73-9151-33792e905ebc","added_by":"auto","created_at":"2025-08-18 06:43:13","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":526288,"visible":true,"origin":"","legend":"\u003cp\u003ePaired line plot of the API value, which shows changes from the initial visit to the final follow-up. The gray lines represent individual data changes, and the red line indicates the mean value. The Wilcoxon signed rank test revealed no significant difference (\u003cem\u003ep \u003c/em\u003e= 0.184).\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7212488/v1/697ecfb3e5734007640e68fc.png"},{"id":91890002,"identity":"814a0824-894b-4de1-bd23-3338306df883","added_by":"auto","created_at":"2025-09-22 16:03:44","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":5730253,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7212488/v1/457074f0-c70b-42b8-b0b7-6ae76a4afe9c.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Clinical characteristics and outcomes of anterior anus in female infants: a multicenter retrospective cohort study","fulltext":[{"header":"Introduction","content":"\u003cp\u003eAnterior anus (AA), also referred to as \u0026ldquo;ectopic anus,\u0026rdquo; \u0026ldquo;anterior ectopic anus,\u0026rdquo; or \u0026ldquo;anterior displacement of the anus,\u0026rdquo; has traditionally been considered a mild form of anorectal malformation (ARM) [1, 2]. However, the absence of a standardized definition has led to inconsistencies in clinical management. Surgical intervention was historically the standard treatment [3, 4], but recent studies suggest that conservative management is often sufficient, with no significant long-term complications [5-7].\u003c/p\u003e\n\u003cp\u003eAA is now precisely defined as a normally shaped anus located anterior to its typical position, fully surrounded by the external sphincter muscle, and with a normal anal caliber. These features distinguish AA from true forms of ARM and support its classification as a normal anatomical variant rather than a pathological anomaly. While symptoms such as constipation or lower urinary tract infections (UTIs) have been reported in patients with AA, their prevalence is similar to that of the general pediatric population [7]. Moreover, recent research suggests that AA does not significantly impact gynecological outcomes in post-menarchal women [5].\u003c/p\u003e\n\u003cp\u003eDespite the establishment of a standardized definition of AA by the 2022 ARM-Net Consortium Consensus [1], its clinical implications remain inadequately explored. Although the association between AA and cardiac, spinal, and renal anomalies \u0026ndash; components of the VACTERL association (vertebral, anorectal, cardiac, tracheoesophageal, renal, and limb anomalies) \u0026ndash; is unclear, no studies have specifically investigated the necessity of VACTERL screening in patients with AA.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThis multicenter study aimed to characterize the clinical features and outcomes of AA and to contribute to the development of clearer clinical guidelines and management strategies for affected patients.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cstrong\u003eEthical considerations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe Institutional Review Boards of all participating institutions approved this study (DSMC IRB 2024-12-059). \u0026nbsp;The requirement for informed consent was waived due to the retrospective and non-interventional nature of the study. All patient data were anonymized and de-identified in accordance with institutional privacy regulations.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStudy design and patient population\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis multicenter retrospective cohort study investigated the clinical characteristics and outcomes of neonates and infants diagnosed with AA. Patients were enrolled from six tertiary referral centers in South Korea from November 2020 to December 2024.\u003c/p\u003e\n\u003cp\u003eThe inclusion criteria were as follows: female infants (aged 0-12 months) who met the diagnostic criteria for AA. The diagnosis was confirmed using the anal position index (API), a quantitative parameter that assesses the anal position relative to the perineal body. According to the ARM-Net Consortium Consensus, an API of \u0026lt; 0.34 in females was considered diagnostic for AA.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe exclusion criteria were as follows: patients with other ARMs, particularly perineal fistula; those with incomplete API measurements or insufficient data on sphincter evaluation; and patients lost to follow-up. One male patient was excluded from the analysis as meaningful conclusions could not be drawn from a single case.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMeasurement of anal caliber and sphincter function\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAnal caliber was assessed using Hegar dilators. The largest Hegar size that could be inserted without resistance was recorded and compared with age-appropriate reference values to confirm normal caliber [8].\u003c/p\u003e\n\u003cp\u003eSphincter function was evaluated through clinical examination. Sphincter muscle integrity was assessed by gently stimulating the perianal skin with a cotton swab to elicit a contraction reflex. Additionally, sphincter tone was subjectively evaluated by observing the constriction around the Hegar dilator during insertion. Electrical stimulation using a muscle-locating stimulator was not performed, as it requires general anesthesia with muscle relaxants and is not feasible in our clinical setting. Only patients with both normal anal caliber and intact sphincter function were included in the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMeasurement of the API\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo determine the API, the relative position of the anal opening within the perineum was assessed. First introduced by Reisner et al. in 1984 [9], the API is calculated as the ratio of perineal length to posterior pelvic floor length.\u003c/p\u003e\n\u003cp\u003eIn female patients, perineal length was measured as the distance from the fourchette to the center of the anus, while the posterior pelvic floor length was defined as the distance from the fourchette to the tip of the coccyx (Fig. 1). All API measurements were performed by pediatric surgeons at each participating center. To minimize interobserver variability, measurement was conducted using standardized anatomical landmarks, and representative images were reviewed in consensus when ambiguity arose. However, inter- and intra-rater reliability was not formally assessed. Representative initial and final follow-up images of patients with AA are presented in Fig. 2.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData collection\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eClinical and demographic data were collected from the electronic medical records of each participating institution. A standardized case report form was used across all six centers to ensure consistent data acquisition. Information collected included patient demographics, clinical presentation, diagnostic findings, and follow-up outcomes.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAt the time of initial diagnosis, the following clinical characteristics were recorded: age, gestational age at birth, and birth weight. Diagnostic data included API measurements, sacral ratio determined by pelvic radiography, spinal ultrasonography findings, and transthoracic echocardiography (TTE) results. The presence of congenital anomalies was assessed based on imaging findings and documented medical history.\u003c/p\u003e\n\u003cp\u003eSupplementary clinical data were collected during follow-up period to evaluate patient outcomes. These included changes in API values and the development of constipation, UTIs, or growth failure. UTIs were defined as a history of hospitalization for fever, excluding cases attributable to upper respiratory infections. For patients who underwent surgical intervention, postoperative API values were recorded to assess anatomical changes.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eOutcome measures\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe primary objective of this study was to assess the long-term clinical outcomes of patients with AA. Primary endpoints included the incidence of constipation, history of recurrent UTIs, longitudinal changes in the API, and the presence of congenital anomalies.\u003c/p\u003e\n\u003cp\u003eSecondary outcomes included growth failure and the need for surgical intervention. Growth failure was assessed using standardized growth curves and age-appropriate weight percentiles. Surgical interventions were analyzed to evaluate the indications for surgery, types of procedures performed, and postoperative outcomes.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDescriptive statistics were used to summarize patient characteristics and clinical outcomes. Continuous variables are presented as means \u0026plusmn; standard deviations or means with standard error of the mean, and categorical variables are reported as frequencies and percentages. Normality was assessed to evaluate changes in API over time, and Wilcoxon signed-rank tests were used to compare paired API values, as the data were not normally distributed. Paired line plots were generated to visualize individual API variations over time. All statistical analyses were performed using the Statistical Package for the Social Sciences, version 29 (IBM corp., Armonk, NY, USA). A \u003cem\u003ep\u003c/em\u003e-value \u0026lt; 0.05 was considered statistically significant.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003ePatient characteristics\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study included 64 female patients diagnosed with AA. The mean API at the time of diagnosis was 0.31 (Table 1). A perineal groove (PG) was frequently observed as a coexisting finding during clinical evaluation. Among the patients, 33 (51.6%) had coexisting PG, while 31 (48.4%) had AA without PG. Of the 33 patients with PG, 18 (54.5%) were classified as having total PG and 15 (45.4%) as having partial PG [10].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAssociated anomalies\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eCongenital anomalies were identified in several patients, with congenital heart disease (CHD) being the most common. Of the 64 patients, 46 underwent TTE, and CHDs were identified in 32 of them. Twenty-six patients had mild CHDs, including atrial septal defect, patent foramen ovale, and patent ductus arteriosus (PDA), which rarely required surgical intervention. Six patients underwent cardiac surgery: two with tetralogy of Fallot, two with atrial septal defect and PDA requiring PDA ligation, and two with atrioventricular septal defects. Among these six patients, three had additional syndromic conditions, including visceral smooth muscle dysfunction syndrome, mosaic Edwards syndrome, and Bardet\u0026ndash;Biedl syndrome.\u003c/p\u003e\n\u003cp\u003ePelvic X-rays were performed in 56 patients, revealing a mean sacral AP ratio of 1.04, with no sacral bone anomalies. Spinal ultrasonography was conducted in 40 patients, all of whom showed no abnormalities. Other congenital anomalies included one case each of Jacobsen syndrome, Pfeiffer syndrome, and polydactyly.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical outcomes and follow-up\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe mean follow-up period was 22.9 months. Constipation occurred in 23% of patients, most of whom responded well to conservative management with intermittent use of laxatives or dietary modifications. No cases of UTI were reported. One patient with mosaic Edwards syndrome exhibited growth failure, which was attributed to the underlying syndrome rather than AA.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAnalysis of patients who underwent surgery\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAmong the 64 patients, three underwent surgical intervention based on parental concern, despite medical reassurance that surgery was not necessary.\u003c/p\u003e\n\u003cp\u003eThe preoperative API values for these three patients were 0.32, 0.30, and 0.31, respectively, and the corresponding postoperative values were 0.33, 0.25, and 0.30. In all three cases, the API remained within the diagnostic range for AA, indicating no significant anatomical correction.\u003c/p\u003e\n\u003cp\u003eTwo of the three patients had concurrent PG, which resolved postoperatively (Fig. 3). None of the surgically treated patients experienced constipation or UTIs during follow-up.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eComparison of the API over time\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo evaluate whether the anal position changed over time, initial and last follow-up API values were compared (Fig. 4). The Wilcoxon signed-rank test revealed no statistically significant difference, indicating that the anal position remained unchanged during follow-up period, regardless of growth or surgical intervention.\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis is the first multicenter retrospective cohort study to analyze the clinical outcomes of AA. Our findings align with previous studies indicating that AA is a benign anatomical variant with minimal long-term morbidity [5, 7]. Notably, the prevalence of constipation and UTIs in our cohort was not significantly different from that in the general pediatric population.\u003c/p\u003e\n\u003cp\u003eConstipation was observed in 23% of patients and was generally manageable with intermittent laxatives or other conservative treatments. This prevalence is consistent with findings from previous Korean studies [11] and reports from the United Kingdom [6], further supporting the notion AA is not a significant risk factor for constipation. Additionally, no cases of UTIs requiring hospitalization were reported during follow-up, suggesting that AA does not increase the risk of UTIs.\u003c/p\u003e\n\u003cp\u003eThe relatively high rate of congenital anomalies was a notable finding, with CHD being the most common. Among the 46 patients who underwent TTE, 32 (69.6%) had CHDs, and 6 (13%) had critical CHDs requiring surgical intervention. Considering that CHD occurs in approximately 1% of the general pediatric population, with 25% of those cases classified as critical, our findings suggest a substantially higher prevalence of CHD in patients with AA [12, 13]. While a recent study from the United Kingdom [6] recommended against routine TTE screening in patients with AA, our results indicate that clinicians should remain vigilant for the possibility of CHD and consider appropriate evaluation when clinically indicated.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn this study, 51.6% of patients with AA also had a coexisting PG, suggesting that PG may frequently occur in conjunction with AA. However, to our knowledge, no previous studies have specifically addressed the relationship between AA and PG. The association between these two conditions remains unclear and warrants further large-scale studies to better understand their relationship and clinical implications.\u003c/p\u003e\n\u003cp\u003ePG is a congenital malformation characterized by a mucosa-lined tract extending from the anus toward the posterior fourchette [14]. Although PG is relatively rare, some reports have described its association with local irritation or infection, occasionally leading to surgical intervention [14-16]. In our cohort, however, despite the coexistence of AA and PG, there was no increased risk of infection observed during follow-up.\u003c/p\u003e\n\u003cp\u003ePrevious studies [10], have demonstrated that PG typically follows a benign course and resolves spontaneously without the need for surgical intervention in most cases. Although those studies focused on patients with isolated PG, the clinical course in our cohort of patients with AA and coexisting PG was similarly benign. Consistent with prior findings, 87.9% of PG cases in our study resolved spontaneously, supporting the feasibility of conservative management [10, 15-17].\u003c/p\u003e\n\u003cp\u003eThe only notable postoperative change among the three patients who underwent surgery was the resolution of PG in those who initially presented with it; the API remained largely unchanged. These findings suggest that surgical intervention did not significantly alter the position of the anus but may have been effective in resolving coexisting PG. Based on our results, a non-surgical approach may be appropriate for patients with AA and PG due to the absence of significant complications and the tendency for spontaneous resolution. However, the limited number of surgical cases in this study precludes drawing definitive conclusions.\u003c/p\u003e\n\u003cp\u003eDespite the strengths of this study, including its multicenter design and standardized data collection, several limitations should be acknowledged. First, as a retrospective study, there is potential for selection bias in both the initial diagnosis and patient follow-up. A standardized prospective study would allow for a more accurate assessment. Second, a longer follow-up period is necessary to evaluate the functional outcomes of AA into adolescence and adulthood, particularly in patients with or without PG.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eAnterior anus does not appear to increase the risk of constipation or UTIs. PG, when present, showed a high rate of spontaneous resolution, supporting the feasibility of conservative management. Although some patients had congenital anomalies, particularly CHDs, the overall morbidity associated with AA was low. Notably, surgical intervention did not change the anal positioning and was primarily effective only in resolving PG when present.\u003c/p\u003e\n\u003cp\u003eGiven the stable long-term outcomes observed in this study, routine surgical correction of AA is generally not necessary. Nonetheless, clinicians should remain vigilant for potential associated anomalies, especially CHD, and consider appropriate screening when clinically indicated. Future prospective studies with longer follow-up are needed to better define the natural history and long-term outcomes of AA. Refining clinical guidelines based on such evidence will help optimize the management of AA, ensuring appropriate and individualized care for affected patients.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflicts of interest:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflicts of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to participate:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eYong Jae Kwon contributed to study design, data collection, statistical analysis, and manuscript drafting.\u003c/p\u003e\n\u003cp\u003eEunyoung Jung supervised the study, contributed to interpretation of results, and critically revised the manuscript.\u003c/p\u003e\n\u003cp\u003eHyunhee Kwon, Suhyeon Ha, and Dae Yeon Kim contributed to patient enrollment and data acquisition.\u003c/p\u003e\n\u003cp\u003eYu Jeong Cho, Ju Yeon Lee, and So Hyun Nam contributed to clinical data interpretation and manuscript editing.\u003c/p\u003e\n\u003cp\u003eAll authors reviewed and approved the final version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability statement:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated and/or analyzed during the current study are not publicly available due to patient privacy concerns but are available from the corresponding author on reasonable request.\u003c/p\u003e\n"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAmerstorfer EE, Schmiedeke E, Samuk I et al (2022) Clinical differentiation between a normal anus, anterior anus, congenital anal stenosis, and perineal fistula: definitions and consequences-the ARM-Net consortium consensus. Children (Basel) 9:831. https://doi.org/10.3390/children9060831\u003c/li\u003e\n\u003cli\u003ePakarinen MP, Rintala RJ (2010) Management and outcome of low anorectal malformations. Pediatr Surg Int 26:1057\u0026ndash;1063. https://doi.org/10.1007/s00383-010-2697-z\u003c/li\u003e\n\u003cli\u003eAbeyaratne M (1991) Posterior transposition of anterior ectopic anus. J Pediatr Surg 26:725\u0026ndash;727. https://doi.org/10.1016/0022-3468(91)90020-t\u003c/li\u003e\n\u003cli\u003eHendren WH (1978) Constipation caused by anterior location of the anus and its surgical correction. J Pediatr Surg 13:505\u0026ndash;512. https://doi.org/10.1016/s0022-3468(78)80315-7\u003c/li\u003e\n\u003cli\u003eDuci M, Fascetti-Leon F, Bogana G, Gamba P, Midrio P (2021) Conservative management of anterior located anus: a medium-long term follow up. J Pediatr Surg 56:2277\u0026ndash;2280. https://doi.org/10.1016/j.jpedsurg.2021.04.003\u003c/li\u003e\n\u003cli\u003eHotonu S, Annett A, Campbell A, Bradnock T, Walker G (2025) Outcomes of management of anterior anus in girls in Glasgow, UK. J Pediatr Surg 60:162023. https://doi.org/10.1016/j.jpedsurg.2024.162023\u003c/li\u003e\n\u003cli\u003eKyrklund K, Pakarinen MP, Taskinen S, Rintala RJ (2015) Bowel function and lower urinary tract symptoms in females with anterior anus treated conservatively: Controlled outcomes into adulthood. J Pediatr Surg 50:1168\u0026ndash;1173. https://doi.org/10.1016/j.jpedsurg.2014.09.074\u003c/li\u003e\n\u003cli\u003eHolcomb GW, Murphy JP, St. Peter SD (2020) Holcomb and Ashcraft\u0026apos;s pediatric surgery. 7th edn. Elsevier, Edinburgh ; New York\u003c/li\u003e\n\u003cli\u003eReisner SH, Sivan Y, Nitzan M, Merlob P (1984) Determination of anterior displacement of the anus in newborn infants and children. Pediatrics 73:216\u0026ndash;217\u003c/li\u003e\n\u003cli\u003eIhn K, Na Y, Ho IG, Oh JT (2020) Clinical characteristics and conservative treatment of perineal groove. J Pediatr Surg 55:1507\u0026ndash;1510. https://doi.org/10.1016/j.jpedsurg.2019.07.017\u003c/li\u003e\n\u003cli\u003eKim HJ, Moon JS, Hwang JH et al (2006) Clinical feature and dietary pattern of infantile constipation under two years of age. Pediatr Gastroenterol Hepatol Nutr 9:31\u0026ndash;38\u003c/li\u003e\n\u003cli\u003eHoffman JI, Kaplan S (2002) The incidence of congenital heart disease. J Am Coll Cardiol 39:1890\u0026ndash;1900. https://doi.org/10.1016/s0735-1097(02)01886-7\u003c/li\u003e\n\u003cli\u003eOster ME, Lee KA, Honein MA, Riehle-Colarusso T, Shin M, Correa A (2013) Temporal trends in survival among infants with critical congenital heart defects. Pediatrics 131:e1502\u0026ndash;e1508. https://doi.org/10.1542/peds.2012-3435\u003c/li\u003e\n\u003cli\u003eKing SK, Levitt MA (2022) Advances in the management of the neonate born with an anorectal malformation. Clin Perinatol 49:965\u0026ndash;979. https://doi.org/10.1016/j.clp.2022.08.002\u003c/li\u003e\n\u003cli\u003eGarcia-Palacios M, Mendez-Gallart R, Cortizo-Vazquez J, Rodriguez-Barca P, Estevez-Martinez E, Bautista-Casasnovas A (2017) Perineal groove in female infants: a case series and literature review. Pediatr Dermatol 34:677\u0026ndash;680. https://doi.org/10.1111/pde.13311\u003c/li\u003e\n\u003cli\u003eSamuk I, Amerstorfer EE, Fanjul M et al (2020) Perineal groove: an anorectal malformation network, consortium study. J Pediatr 222:207\u0026ndash;212. https://doi.org/10.1016/j.jpeds.2020.03.026\u003c/li\u003e\n\u003cli\u003eEsposito C, Giurin I, Savanelli A, Alicchio F, Settimi A (2011) Current trends in the management of pediatric patients with perineal groove. J Pediatr Adolesc Gynecol 24:263\u0026ndash;265. https://doi.org/10.1016/j.jpag.2011.02.011\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Table 1","content":"\u003cp\u003e\u003cstrong\u003eTable 1\u003c/strong\u003e Demographics and clinical characteristics of female infants diagnosed with anterior anus (\u003cem\u003en\u003c/em\u003e = 64)\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 255px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCharacteristics\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 283px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eValue, n (%) or Mean \u0026plusmn; SEM\u003c/strong\u003e\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 255px;\"\u003e\n \u003cp\u003eGestational age (weeks)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 283px;\"\u003e\n \u003cp\u003e37.5 \u0026plusmn; 0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 255px;\"\u003e\n \u003cp\u003eBirth weight (g)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 283px;\"\u003e\n \u003cp\u003e2916 \u0026plusmn; 70\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 255px;\"\u003e\n \u003cp\u003eAnal position index\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 283px;\"\u003e\n \u003cp\u003e0.31 \u0026plusmn; 0.004\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 255px;\"\u003e\n \u003cp\u003ePerineal groove\u003c/p\u003e\n \u003cp\u003eTotal\u003c/p\u003e\n \u003cp\u003ePartial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 283px;\"\u003e\n \u003cp\u003e33/64 (51.6)\u003c/p\u003e\n \u003cp\u003e18/33 (54.5)\u003c/p\u003e\n \u003cp\u003e15/33 (45.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 255px;\"\u003e\n \u003cp\u003eAssociated anomalies\u003c/p\u003e\n \u003cp\u003eCongenital heart disease (CHD)\u003c/p\u003e\n \u003cp\u003eMild\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003eCritical\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003eOthers\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 283px;\"\u003e\n \u003cp\u003e35/64 (54.7)\u003c/p\u003e\n \u003cp\u003e32\u003c/p\u003e\n \u003cp\u003e26 (81.3)\u003c/p\u003e\n \u003cp\u003e6 (18.8)\u003c/p\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 255px;\"\u003e\n \u003cp\u003eFollow-up duration (months)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 283px;\"\u003e\n \u003cp\u003e22.8 \u0026plusmn; 1.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003csup\u003ea\u003c/sup\u003eSEM, standard error of the mean\u003c/p\u003e\n\u003cp\u003e\u003csup\u003eb\u003c/sup\u003eMild CHD refers to conditions not requiring surgical intervention (e.g., small atrial septal defect, small patent foramen ovale, small patent ductus arteriosus)\u003c/p\u003e\n\u003cp\u003e\u003csup\u003ec\u003c/sup\u003eCritical CHD refers to conditions requiring surgical intervention or procedures within the first year of life\u003c/p\u003e\n\u003cp\u003e\u003csup\u003ed\u003c/sup\u003eOther syndromic anomalies include mosaic Edward syndrome, Jacobsen syndrome, Pfeiffer syndrome, Bardet\u0026ndash;Biedl syndrome, and visceral smooth muscle dysfunction syndrome\u003c/p\u003e\n"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"pediatric-surgery-international","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pesi","sideBox":"Learn more about [Pediatric Surgery International](http://link.springer.com/journal/383)","snPcode":"383","submissionUrl":"https://submission.nature.com/new-submission/383/3","title":"Pediatric Surgery International","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Anterior anus, Anorectal malformation, Perineal groove, Infants, Constipation, Urinary tract infection","lastPublishedDoi":"10.21203/rs.3.rs-7212488/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7212488/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground:\u003c/strong\u003e Anterior anus (AA) is a congenital anatomical variant with unclear clinical implications and management strategies. This study evaluated the clinical features, associated anomalies, and outcomes of AA in female infants.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e This multicenter retrospective cohort study included infants diagnosed with AA between 2020 and 2024 at six tertiary referral centers in South Korea. The clinical characteristics, coexisting anomalies, and outcomes including constipation and urinary tract infections were analyzed.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e Among the 64 patients included in this study, 51.6% had a concomitant perineal groove. Congenital heart diseases were the most common coexisting anomaly, occurring in 32 patients. During a mean follow-up of 22.9 months, constipation was observed in 23% of the patients. Urinary tract infections were not observed. The perineal groove resolved spontaneously in 87.9% of cases.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e AA is a benign anatomical variant that does not increase the risk of constipation or urinary tract infections. Given the observed association with congenital heart disease, cardiac evaluation should be considered when clinically indicated.\u003c/p\u003e","manuscriptTitle":"Clinical characteristics and outcomes of anterior anus in female infants: a multicenter retrospective cohort study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-18 06:27:09","doi":"10.21203/rs.3.rs-7212488/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-09-01T13:54:06+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-26T14:16:43+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"73717570166088760444978441168372855108","date":"2025-08-15T14:30:53+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"275890855612786899094903416563175788536","date":"2025-08-12T18:55:04+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-10T14:57:30+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-01T19:18:28+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-01T05:53:26+00:00","index":"","fulltext":""},{"type":"submitted","content":"Pediatric Surgery International","date":"2025-07-25T08:59:56+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"pediatric-surgery-international","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pesi","sideBox":"Learn more about [Pediatric Surgery International](http://link.springer.com/journal/383)","snPcode":"383","submissionUrl":"https://submission.nature.com/new-submission/383/3","title":"Pediatric Surgery International","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"a37bef4d-fa67-4013-bc6b-ac82d40c47bd","owner":[],"postedDate":"August 18th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-09-22T16:02:48+00:00","versionOfRecord":{"articleIdentity":"rs-7212488","link":"https://doi.org/10.1007/s00383-025-06196-3","journal":{"identity":"pediatric-surgery-international","isVorOnly":false,"title":"Pediatric Surgery International"},"publishedOn":"2025-09-16 15:57:13","publishedOnDateReadable":"September 16th, 2025"},"versionCreatedAt":"2025-08-18 06:27:09","video":"","vorDoi":"10.1007/s00383-025-06196-3","vorDoiUrl":"https://doi.org/10.1007/s00383-025-06196-3","workflowStages":[]},"version":"v1","identity":"rs-7212488","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7212488","identity":"rs-7212488","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}