{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,1]],"date-time":"2026-07-01T08:47:58Z","timestamp":1782895678987,"version":"3.54.5"},"reference-count":12,"publisher":"SAGE Publications","license":[{"start":{"date-parts":[[2026,6,28]],"date-time":"2026-06-28T00:00:00Z","timestamp":1782604800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Ultrasound"],"abstract":"<jats:sec>\n                    <jats:title>Introduction:<\/jats:title>\n                    <jats:p>Caesarean scar ectopic pregnancy (CSEP) is a potentially serious complication of caesarean section (C-section) which consists of the implantation of the gestational sac (GS) in the hysterotomy scar. All women with a history of C-section are at risk for CSEP. Early diagnosis and treatment are critical to avoid maternal morbidity and mortality. There is overlap in the sonographic appearance of CSEP, low-lying normal pregnancy, cervical ectopic pregnancy and miscarriage in progress. In 2022, a standardised sonographic evaluation and reporting system for CSEP in the first trimester was published to raise awareness of this entity. We aim to provide a practical guide to the sonographer by outlining the pertinent obstetric history, imaging findings and differential diagnoses in these patients.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Case Report:<\/jats:title>\n                    <jats:p>We report three cases of CSEP, diagnosed by ultrasonography in the first trimester. We also report three different conditions that may mimic CSEP. We include the clinical details, sonographic findings and patient outcomes.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Discussion:<\/jats:title>\n                    <jats:p>The incidence of CSEP is suspected to be under-recognised and thus underreported. CSEP presents a substantial risk for severe maternal complications including uterine rupture, severe hemorrhage and placenta accreta spectrum disorders. This is complicated by challenges in securing an early diagnosis. When a first-trimester ultrasound reveals a GS in the lower third of the uterus, the sonographer must consider the differential diagnoses herein.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion:<\/jats:title>\n                    <jats:p>We will present the recommended criteria using cases demonstrating the sonographic findings. Raising awareness of the four key sonographic markers of CSEP may improve sonographer detection rates, thus facilitating better patient management.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1177\/1742271x261444869","type":"journal-article","created":{"date-parts":[[2026,6,29]],"date-time":"2026-06-29T05:07:27Z","timestamp":1782709647000},"update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":0,"title":["Sonographic evaluation of low-lying gestational sac in the first trimester: A sonographer\u2019s guide to identify caesarean scar ectopic pregnancy"],"prefix":"10.1177","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6145-2981","authenticated-orcid":false,"given":"Karen","family":"Letourneau","sequence":"first","affiliation":[{"name":"Island Health, Victoria, BC, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-7636-0993","authenticated-orcid":false,"given":"Amandeep","family":"Dusanj","sequence":"additional","affiliation":[{"name":"Island Health, Victoria, BC, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-8269-9275","authenticated-orcid":false,"given":"Sarah","family":"Barrett","sequence":"additional","affiliation":[{"name":"Vancouver Coastal Health, BC, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"179","published-online":{"date-parts":[[2026,6,28]]},"reference":[{"key":"e_1_3_3_2_2","doi-asserted-by":"crossref","unstructured":"Verberkt C Jordans IPM van den Bosch T et al. How to perform standardized sonographic examination of cesarean scar pregnancy in the first trimester. Ultrasound Obstet Gynecol 2024; 64(3): 412\u2013418. https:\/\/doi.org\/10.1002\/uog.27604","DOI":"10.1002\/uog.27604"},{"key":"e_1_3_3_3_2","doi-asserted-by":"publisher","unstructured":"Maymon R Svirsky R Smorgick N et al. Fertility performance and obstetric outcomes among women with previous cesarean scar pregnancy. J Ultrasound Med. 2011;30(9):1179\u20131184. DOI: 10.7863\/jum.2011.30.9.1179. Erratum in: J Ultrasound Med 2011; 30(10): 1444.","DOI":"10.7863\/jum.2011.30.9.1179"},{"key":"e_1_3_3_4_2","doi-asserted-by":"crossref","unstructured":"Comune R Liguori C Tamburrini S et al. MRI assessment of cesarean scar pregnancies: a case series. J Clin Med 2023; 12(23): 7241. https:\/\/doi.org\/10.3390\/jcm12237241","DOI":"10.3390\/jcm12237241"},{"key":"e_1_3_3_5_2","doi-asserted-by":"crossref","unstructured":"Jordans IPM Verberkt C De Leeuw RA. Definition and sonographic reporting system for cesarean scar pregnancy in early gestation: modified Delphi method. Ultrasound Obstet Gynecol 2022; 59(4): 437\u2013449. https:\/\/doi.org\/10.1002\/uog.24815","DOI":"10.1002\/uog.24815"},{"key":"e_1_3_3_6_2","doi-asserted-by":"crossref","unstructured":"Rodgers SK Horrow MM Doubilet PM. A lexicon for first-trimester US: Society of Radiologists in Ultrasound Consensus conference recommendations. Radiology 2024; 312(2): e240122. https:\/\/doi.org\/10.1148\/radiol.240122","DOI":"10.1148\/radiol.240122"},{"key":"e_1_3_3_7_2","doi-asserted-by":"crossref","unstructured":"Kennedy A Debbink M Griffith A. Cesarean scar ectopic pregnancy: a do-not-miss diagnosis. Radiographics 2024; 44(7): e230199. https:\/\/doi.org\/10.1148\/rg.230199.PMID:38843098","DOI":"10.1148\/rg.230199"},{"key":"e_1_3_3_8_2","doi-asserted-by":"crossref","unstructured":"P\u0119draszewski P Wla\u017alak E Panek W et al. Cesarean scar pregnancy\u2013a new challenge for obstetricians. J Ultrason 2018; 18(72): 56\u201362. https:\/\/doi.org\/10.15557\/JoU.2018.0009","DOI":"10.15557\/JoU.2018.0009"},{"key":"e_1_3_3_9_2","doi-asserted-by":"crossref","unstructured":"Morlando M Conte A Schiattarella A. Reproductive outcome after cesarean scar pregnancy. Best Pract Res Clin Obstet Gynaecol 2023; 91: 102362. https:\/\/doi.org\/10.1016\/j.bpobgyn.2023.102362","DOI":"10.1016\/j.bpobgyn.2023.102362"},{"key":"e_1_3_3_10_2","doi-asserted-by":"crossref","unstructured":"Kaelin Agten A Jurkovic D Timor-Tritsch I et al. First-trimester cesarean scar pregnancy: a comparative analysis of treatment options from the international registry. Am J Obstet Gynecol 2024; 230(6): 669e1\u2013669e19. https:\/\/doi.org\/10.1016\/j.ajog.2023.10.028","DOI":"10.1016\/j.ajog.2023.10.028"},{"key":"e_1_3_3_11_2","doi-asserted-by":"crossref","unstructured":"Huang J Phillips C Moshiri M. Scarred for life: a review of cesarean section scar pregnancy and potential pitfalls in diagnosis. Abdom Radiol (NY) 2023; 48(8): 2672\u20132683. https:\/\/doi.org\/10.1007\/s00261-023-03953-7","DOI":"10.1007\/s00261-023-03953-7"},{"key":"e_1_3_3_12_2","doi-asserted-by":"crossref","unstructured":"Timor-Tritsch IE Monteagudo A Cali G et al. Cesarean scar pregnancy and early placenta accreta share common histology. Ultrasound Obstet Gynecol 2014; 43(4): 383\u2013395. https:\/\/doi.org\/10.1002\/uog.13282","DOI":"10.1002\/uog.13282"},{"key":"e_1_3_3_13_2","doi-asserted-by":"crossref","unstructured":"Timor-Tritsch IE D\u2019Antonio F Monteagudo A et al. Cesarean scar pregnancy spectrum. 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