Article Title: ”Uterine Dehiscence: A Diagnostic Conundrum in Repeat Cesarean Deliveries”Author Information: Pamela Sarue, M.D.1, Nicholas Eynon2, Reine A. Zbeidy M.D.1,21Division of Obstetric Anesthesiology, University of Miami, Jackson Memorial Hospital, Miami, FL2University of Miami Miller School of Medicine, Miami, FLInstitutional title/position of Reine A. Zbeidy:Associate Professor of Clinical AnesthesiologyProgram Director of Obstetric Anesthesia Fellowshiprzbeidy@med.miami.eduAuthor Contribution Statement:Dr. Pamela Sarue: Conceptualization, Investigation, Project administration, Writing - original draft, Writing - review & editingMr. Nicholas Eynon: Writing - review & editingDr. Reine A. Zbeidy: Conceptualization, Investigation, Project administration, Supervision, Writing - original draftCorresponding Author: Reine A. Zbeidy1600 NW 14th St, Miami, 33136Rzbeidy@miami.eduClinical trial number and registry URL: Not applicablePrior Presentations: Not applicableAcknowledgements: Not applicableWord Count (manuscript): 250 wordsAbbreviated Title: Not applicableSummary Statement: Not applicableFunding Statement: Support was provided solely from institutional and/or departmental sourcesConflicts of Interest: The authors declare no competing interestsPatient consent: Patient consent signed and collected in accordance with the journal’s patient consent policyKey Clinical Message: Uterine dehiscence (UD), often asymptomatic and underdiagnosed, is a significant risk in patients with prior cesarean deliveries. It can lead to complications like uterine rupture, increasing maternal and neonatal morbidity. Improved diagnostic protocols, particularly antenatal imaging, are essential to differentiate UD from placenta accreta spectrum, optimize resource utilization, and enhance patient outcomes.Manuscript:A 31-year-old G5P4004 woman was scheduled for repeat cesarean delivery (CD). She had 4 prior CD, anterior placenta, and suspected placental accreta, which was intra-operatively diagnosed as uterine dehiscence (UD) (Figure 1). Most UD cases are asymptomatic with no bleeding(1), and lack of standard diagnostic protocol makes their evaluation and management challenging(2).UD is a partial division of the uterus that does not affect all three layers (endometrium, myometrium, and perimetrium)(1). It is more common with each additional prior CD(2). With CD rates increasing from 5% to 30% in the past 35 years(2), this condition merits attention.UD may lead to a ”uterine window,” a thin uterine wall segment that reveals the fetus through the myometrium, as illustrated in Figure 1(1). Often undiagnosed due to the lack of a diagnostic protocol, it can be identified intraoperatively during repeat CD or antenatally between pregnancies on transvaginal ultrasound(2). A study of patients with prior CD (n=21,420) found an incidence of 10.1% for UD and 2.8% for uterine rupture, which is UD’s most concerning complication(3).Uterine rupture increases maternal and neonatal morbidity(1). Its potential for severe impact on patient hemodynamic stability necessitates maintaining clinical suspicion for this complication in patients with prior CD presenting with abnormal imaging.The preoperative misdiagnosis of a uterine window as placenta accreta spectrum demands additional resources such as more invasive monitoring, blood product availability, and multi-service involvement, all of which could be avoided with more accurate diagnostic tools. This underscores the necessity for advanced diagnostic modalities for uterine dehiscence and windows(2).References:Togioka BM, Tonismae T. Uterine Rupture. In: StatPearls . Treasure Island (FL): StatPearls Publishing; February 28, 2023.Eleje GU, Udigwe GO, Okafor CG, et al. Intra-operative Diagnosis of Lower Segment Scar Dehiscence in a Second Gravida After One Previous Lower Segment Cesarean Section: Should We Advocate for Routine Antenatal Uterine Scar Thickness Testing?. Clin Med Insights Case Rep . 2023;16:11795476231164379. Published 2023 Mar 29. doi:10.1177/11795476231164379Fogelberg M, Baranov A, Herbst A, Vikhareva O. Underreporting of complete uterine rupture and uterine dehiscence in women with previous cesarean section. J Matern Fetal Neonatal Med . 2017;30(17):2058-2061. doi:10.1080/14767058.2016.1236249Figure 1: Intraoperative photograph demonstrating a markedly thinned and bulging lower uterine segment at the site of the old cesarean scar, consistent with uterine dehiscence.