Prenatal Ultrasound Diagnosis of a Rare Morgagni Hernia: A Case Report

Prenatal Ultrasound Diagnosis of a Rare Morgagni Hernia: A Case Report | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report Prenatal Ultrasound Diagnosis of a Rare Morgagni Hernia: A Case Report Ting Pan, Tao Li, Tiangang Li, Wenjing Pang, Gang Wang, Bin Ma This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8609285/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 21 Apr, 2026 Read the published version in BMC Pregnancy and Childbirth → Version 1 posted 13 You are reading this latest preprint version Abstract This case report presents a rare instance of fetal Morgagni hernia. A 27-week pregnant woman was found to have a fetal Morgagni hernia during a routine prenatal examination. The condition likely resulted from a congenital defect in the diaphragm, characterized by failure of the retrosternal portion to close, leading to communication between the pericardial and peritoneal cavities. A portion of the liver herniated through this defect into the retrosternal region, compressing the pericardium and causing massive pericardial effusion, along with lung compression and subsequent pulmonary hypoplasia. Morgagni hernia Pericardial effusion Prenatal Three-dimensional ultrasound Figures Figure 1 Figure 2 Figure 3 Introduction Morgagni Hernia, also known as retrosternal hernia, is a rare type of congenital diaphragmatic hernia (CDH), accounting for approximately 3%–5% of all CDH cases. Its anatomical basis is the sternocostal triangles (also known as the foramina of Morgagni) located bilaterally to the sternum. This area represents a potential site of weakness between the sternal and costal muscular fibers of the diaphragm. Herniation of abdominal contents through this defect into the thoracic cavity results in a Morgagni hernia. Due to the reinforcing effect of the pericardium on the anterior portion of the left diaphragm, the left sternocostal triangle is relatively more robust. Consequently, the vast majority of these hernias occur on the right side. This study presents a retrospective analysis of a fetal case diagnosed prenatally with a right-sided Morgagni hernia. The herniated content consisted of a portion of the liver, whose intrusion led to massive pericardial effusion, lung compression, and pulmonary hypoplasia. Accurate prenatal ultrasound diagnosis is crucial for the perinatal management of this condition. By examining the clinical data of this case, this article aims to provide a reference for the diagnosis and treatment of Morgagni hernia. Case Presentation The patient was a 28-year-old female with no significant family history of genetic disorders. Physical examination and laboratory tests revealed no remarkable abnormalities. She was transferred to our institution for further evaluation at 27 weeks of gestation following an ultrasound finding of massive fetal pericardial effusion. Ultrasonographic examination revealed the following: A two-dimensional transverse view of the fetal chest demonstrated a large pericardial effusion surrounding the heart. The right lung measured 19 mm × 11 mm and the left lung 17 mm × 9 mm, with both lung lobes appearing compressed, displaced posteriorly, reduced in volume, and closely apposed to the posterior chest wall (Fig. 1 a). A sagittal view of the chest showed a retrosternal isoechoic mass measuring approximately 20 mm × 10 mm, with an echo pattern similar to that of the liver parenchyma (Fig. 1 b). Three-dimensional ultrasound, in both transverse and sagittal planes, more clearly demonstrated that the vascular supply to this mass originated from the intrahepatic portal vein (Fig. 2 a), confirming herniation of a portion of the liver into the thoracic cavity through a diaphragmatic defect (Fig. 2 b). Based on the collective imaging findings, the prenatal ultrasound diagnosis was established as: a retrosternal isoechoic mass, consistent with Morgagni hernia, accompanied by massive pericardial effusion. Fetal magnetic resonance imaging (MRI) also confirmed the herniation of a part of the liver (marked by an asterisk in the image) into the thoracic cavity along with a significant pericardial effusion (Fig. 3 a). To alleviate persistent compression of both lungs by the pericardial effusion and prevent further pulmonary hypoplasia, a pericardiocentesis was successfully performed in utero. Follow-up examination four weeks post-procedure showed improvement in lung compression and better lung expansion compared to prior findings. The pregnant woman delivered a male infant weighing 2400 g via cesarean section at 39⁺ weeks of gestation, with Apgar scores of 9 at 1 minute and 10 at 5 minutes. The newborn was transferred to our Neonatal Intensive Care Unit(NICU) on the same day and was placed on conventional mechanical ventilation via endotracheal intubation. A right-sided diaphragmatic hernia repair was performed on the second postnatal day. Intraoperative findings revealed an approximately 2 cm × 2 cm defect in the anteromedial portion of the right diaphragm, through which part of the right hepatic lobe had herniated into the right thoracic cavity. A hernial sac and a distended pericardium were observed posterior to the sternum, with a portion of the pericardium forming the wall of the hernial sac. No significant fluid accumulation was noted upon incision. The newborn continued to receive ventilatory support postoperatively, with gradual improvement in respiratory status. Subsequent follow-up indicated a favorable recovery. Discussion In prenatal ultrasound examination, Morgagni hernia typically manifests as herniation of the liver into the thoracic cavity through a diaphragmatic defect. As the condition progresses, it may gradually lead to pulmonary compression and pericardial effusion. In the present case, two-dimensional prenatal ultrasound identified the fetal diaphragmatic defect and abnormal liver position. Tracing the hernial orifice allowed for a preliminary assessment of the origin of the herniated contents. Three-dimensional imaging provided a more clearer visualization of the margins of the diaphragmatic defect and the anatomical relationship between the hernial sac and the diaphragm. This enhanced visualization contributes to improved diagnostic sensitivity and accuracy. In this case of Morgagni hernia accompanied by massive pericardial effusion, the precise underlying mechanism remains incompletely understood. Existing research suggests potential associations with the following hypotheses [4]: ( 1 ) obstruction of hepatic venous return leading to congestion and exudation; ( 2 ) compression of the thoracic duct resulting in lymphatic accumulation. Although the pericardial effusion exerted posterior compression on both lungs, increasing the risk of pulmonary hypoplasia, the fetus in this case did not exhibit cardiac dysfunction or signs of cardiac tamponade. This may be attributed to the gradual accumulation of fluid, allowing for compensatory pericardial dilation. Therefore, the combined use of prenatal two-dimensional and three-dimensional ultrasonography enables more accurate identification of the diaphragmatic defect location, tracing of the origin of the herniated contents, and assessment of the spatial relationship between the effusion and lung tissue, all of which hold significant diagnostic value for this condition. Furthermore, pericardial effusion caused by Morgagni hernia must be differentiated from pleural effusion. The latter typically presents with bilateral lungs displaced centrally, floating within the accumulated fluid, whereas the former results in posterior compression of both lungs. This distinction is a critical diagnostic point and is closely related to subsequent clinical management strategies. The prognosis of this condition primarily depends on the developmental status of the lungs and heart. In this case, intrauterine pericardiocentesis performed at 27 weeks of gestation effectively alleviated pulmonary compression, and follow-up examinations demonstrated improved lung expansion. Following birth, the infant underwent surgical repair of the diaphragmatic hernia and recovered well, with subsequent follow-up yielding satisfactory outcomes. Therefore, accurate prenatal ultrasound diagnosis plays a crucial role in guiding perinatal management. Morgagni hernia should also be differentiated from the following conditions: Hiatal hernia typically appears on ultrasound as a diaphragmatic sac-like structure, which may exhibit gastric mucosal folds or air-fluid levels and maintains continuity with the sub-diaphragmatic stomach. Pulmonary sequestration, often presenting as a solid-cystic lesion in the posterior basal segment of the lower lobe, can be diagnosed by tracing its anomalous systemic arterial supply using three-dimensional ultrasound. Pericardial tumors manifest as an intracardiac or pericardial mass with an intact diaphragm and are frequently complicated by cardiac tamponade and fetal hydrops. Abbreviations CDH Congenital Diaphragmatic Hernia MRI Magnetic Resonance Imaging NICU Neonatal Intensive Care Unit H Heart P Pericardial Effusion L Liver SP Spine CM Centimeter MM Millimeter G Gram Declarations Acknowledgments The authors would like to express their gratitude to the patients and their families who participated in this study.We would also like to thank the medical and research staff at Gansu Maternal and Child Health Hospital for their support and assistance in conducting this research. Author contributions I) Conception and design: T Pan,T Li; (II) Administrative support: B Ma, T Li; (III) Provision of study materials or patients: B Ma; (IV) Collection and assembly of data: T Pan, T Li,W Pang, G Wang; (V) Manuscript writing: All authors; (VI) Final approval of manuscript: All authors. Funding This study was supported by the Outstanding Talent Program (Grant No. GMCCH2025-2-2-02). Data availability : not applicable. Ethics approval and consent to participate All procedures performed in this study were in accordance with the ethical standards of the Medical Ethics Committee of Gansu Provincial Maternity and Child-Care Hospital and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient’s next of kin for publication of this article and any accompanying images. A copy of the written consent is available for review by the editorial office of this journal. Consent for publication The clinical data and imaging used in this study were obtained with the written informed consent of the legal guardians of the fetuses involved in the research. The consent covers the use of these materials for scientific research and publication purposes. All materials will be made freely available in accordance with the relevant Creative Commons license. Competing interests The authors declare no competing interests. Author details 1 Ultrasound Medicine Center, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, People’s Republic of China. Clinical trial number : not applicable. References Liu Y, Zhang Y, Ren X, et al. There were 2 cases of Morgagni hernia. Chin J Laparosc Surg (Electronic edition). 2018;11(4):245–6. Haino K, Serikawa T, Itsukaichi M, et al. Morgagni hernia with massive pericardial effusion diagnosed in the second trimester: prenatal diagnosis and perinatal management. Fetal Diagn Ther. 2011;29(1):108–10. Zamprakou A, Berg C, Strizek B, et al. Morgagni hernia presenting with massive pericardial effusion and ascites: prenatal management by thoraco-amniotic shunting and fetal endoscopic tracheal occlusion (FETO) and review of the literature. Arch Gynecol Obstet. 2016;294(5):953–8. Babic I, Al-Jobair H, Al Towaijri O, et al. Prenatal Diagnosis and Management of a Rare Central Tendon Defect Type of Congenital Diaphragmatic Hernia with a Massive Pericardial Effusion. Case Rep Obstet Gynecol. 2020;2020:6798253. Xiaoqing G, Qin D, Hailang Y, Junhua L, Liang Q. One case of Morgagni hernia [J]. J Practical Radiol. 2022;38(9):1563–4. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 21 Apr, 2026 Read the published version in BMC Pregnancy and Childbirth → Version 1 posted Editorial decision: Revision requested 05 Mar, 2026 Reviews received at journal 04 Mar, 2026 Reviewers agreed at journal 26 Feb, 2026 Reviews received at journal 18 Feb, 2026 Reviews received at journal 16 Feb, 2026 Reviewers agreed at journal 16 Feb, 2026 Reviewers agreed at journal 11 Feb, 2026 Reviewers agreed at journal 09 Feb, 2026 Reviewers invited by journal 09 Feb, 2026 Editor invited by journal 19 Jan, 2026 Editor assigned by journal 16 Jan, 2026 Submission checks completed at journal 16 Jan, 2026 First submitted to journal 15 Jan, 2026 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. 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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-8609285","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":588522436,"identity":"6e60f5f0-e217-496c-a0cb-068ee22430b5","order_by":0,"name":"Ting Pan","email":"","orcid":"","institution":"Ultrasound Medicine Center, Gansu Provincial Maternity and Child-care Hospital","correspondingAuthor":false,"prefix":"","firstName":"Ting","middleName":"","lastName":"Pan","suffix":""},{"id":588522437,"identity":"45939323-e7e1-400d-b600-36a2883c9661","order_by":1,"name":"Tao Li","email":"","orcid":"","institution":"Ultrasound Medicine Center, Gansu Provincial Maternity and Child-care Hospital","correspondingAuthor":false,"prefix":"","firstName":"Tao","middleName":"","lastName":"Li","suffix":""},{"id":588522438,"identity":"47e79443-9c18-4311-96fd-7f0ce8114064","order_by":2,"name":"Tiangang Li","email":"","orcid":"","institution":"Ultrasound Medicine Center, Gansu Provincial Maternity and Child-care Hospital","correspondingAuthor":false,"prefix":"","firstName":"Tiangang","middleName":"","lastName":"Li","suffix":""},{"id":588522439,"identity":"a14c8fa0-7cac-452e-bdfc-08814f950f4a","order_by":3,"name":"Wenjing Pang","email":"","orcid":"","institution":"Ultrasound Medicine Center, Gansu Provincial Maternity and Child-care Hospital","correspondingAuthor":false,"prefix":"","firstName":"Wenjing","middleName":"","lastName":"Pang","suffix":""},{"id":588522440,"identity":"a641bd1c-7240-4482-a7f1-e502885946ff","order_by":4,"name":"Gang Wang","email":"","orcid":"","institution":"Ultrasound Medicine Center, Gansu Provincial Maternity and Child-care Hospital","correspondingAuthor":false,"prefix":"","firstName":"Gang","middleName":"","lastName":"Wang","suffix":""},{"id":588522441,"identity":"58746de8-0a59-426d-9b86-741c14c075de","order_by":5,"name":"Bin Ma","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAxklEQVRIiWNgGAWjYBACNvnjBx//+fGP2b69gUgtfBI8yQa8PQfYDXgOEKlFToLBTIKH7QC/gUQCsQ6Tbkg2kOC5I20u+XjjDYYam2jCWmQOHnxgYPHM2HJ2WrEFw7G03AaCWhgSkg0SeJiTGW7nmEkwNhwmSouZxAE25vqGm2eI1SKRYCbZwHaY2eAGD7FaeM4kGzP2pDFL9gD9kkCMX+Tb2w8+Zvhhw8zPfnjjjQ81NoS1IAPiowZJC6k6RsEoGAWjYGQAAPUEPIDSH+3AAAAAAElFTkSuQmCC","orcid":"","institution":"Ultrasound Medicine Center, Gansu Provincial Maternity and Child-care Hospital","correspondingAuthor":true,"prefix":"","firstName":"Bin","middleName":"","lastName":"Ma","suffix":""}],"badges":[],"createdAt":"2026-01-15 10:08:13","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8609285/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8609285/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12884-026-09119-9","type":"published","date":"2026-04-21T15:59:03+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":102441795,"identity":"2fffb76b-f4b8-487a-a06f-0a5b2a8323b9","added_by":"auto","created_at":"2026-02-11 17:00:31","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":643270,"visible":true,"origin":"","legend":"\u003cp\u003ea, Prenatal two-dimensional transverse view of the chest demonstrates a large fluid collection (H) surrounding the fetal heart, identified as pericardial effusion (P). The lungs (white triangles) are compressed and displaced posteriorly within the thorax. b, Sagittal view of the fetal chest shows herniation of a portion of the abdominal liver (L, indicated by asterisk) into the thoracic cavity, specifically into the pericardial space, which is surrounded by a significant pericardial effusion (P). (h: heart, P: pericardial effusion, L: liver, *: mass)\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8609285/v1/dc6ede876e9b36da99e19842.png"},{"id":102441794,"identity":"aa082a5d-ce0b-4404-a4af-04edc5cf762d","added_by":"auto","created_at":"2026-02-11 17:00:31","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1100650,"visible":true,"origin":"","legend":"\u003cp\u003ea, Prenatal three-dimensional transverse view of the chest reveals hepatic vasculature (white arrow) extending from the abdomen into the thorax, confirming hepatic herniation through the diaphragmatic defect. The right lung (white triangle) is compressed posteriorly. b, Sagittal view demonstrates a retrosternal mass (asterisk) posterior to the sternum (St). (h: heart, P: pericardial effusion, L: liver, Sp: spine, *: mass)\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8609285/v1/e6fe95cbf834cbc44014720a.png"},{"id":102441796,"identity":"ed5bb9b8-1097-41d9-9b31-79d19b0e9ea1","added_by":"auto","created_at":"2026-02-11 17:00:31","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":265065,"visible":true,"origin":"","legend":"\u003cp\u003ea, Prenatal MRI confirms herniation of a portion of the abdominal liver (L, indicated by asterisk) into the fluid-filled pericardial cavity (P). (P: pericardial effusion, L: liver, *: mass)\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-8609285/v1/b1110f8d30297ef24cedb277.png"},{"id":107928087,"identity":"b115535c-8fdc-4938-bfcc-ed3c8f4f3c73","added_by":"auto","created_at":"2026-04-27 16:07:33","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3871215,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8609285/v1/236bf906-d083-467b-87e4-c4e530908ef2.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Prenatal Ultrasound Diagnosis of a Rare Morgagni Hernia: A Case Report","fulltext":[{"header":"Introduction","content":"\u003cp\u003eMorgagni Hernia, also known as retrosternal hernia, is a rare type of congenital diaphragmatic hernia (CDH), accounting for approximately 3%\u0026ndash;5% of all CDH cases. Its anatomical basis is the sternocostal triangles (also known as the foramina of Morgagni) located bilaterally to the sternum. This area represents a potential site of weakness between the sternal and costal muscular fibers of the diaphragm. Herniation of abdominal contents through this defect into the thoracic cavity results in a Morgagni hernia. Due to the reinforcing effect of the pericardium on the anterior portion of the left diaphragm, the left sternocostal triangle is relatively more robust. Consequently, the vast majority of these hernias occur on the right side. This study presents a retrospective analysis of a fetal case diagnosed prenatally with a right-sided Morgagni hernia. The herniated content consisted of a portion of the liver, whose intrusion led to massive pericardial effusion, lung compression, and pulmonary hypoplasia. Accurate prenatal ultrasound diagnosis is crucial for the perinatal management of this condition. By examining the clinical data of this case, this article aims to provide a reference for the diagnosis and treatment of Morgagni hernia.\u003c/p\u003e\n"},{"header":"Case Presentation","content":"\u003cp\u003eThe patient was a 28-year-old female with no significant family history of genetic disorders. Physical examination and laboratory tests revealed no remarkable abnormalities. She was transferred to our institution for further evaluation at 27 weeks of gestation following an ultrasound finding of massive fetal pericardial effusion. Ultrasonographic examination revealed the following: A two-dimensional transverse view of the fetal chest demonstrated a large pericardial effusion surrounding the heart. The right lung measured 19 mm \u0026times; 11 mm and the left lung 17 mm \u0026times; 9 mm, with both lung lobes appearing compressed, displaced posteriorly, reduced in volume, and closely apposed to the posterior chest wall (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea). A sagittal view of the chest showed a retrosternal isoechoic mass measuring approximately 20 mm \u0026times; 10 mm, with an echo pattern similar to that of the liver parenchyma (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb). Three-dimensional ultrasound, in both transverse and sagittal planes, more clearly demonstrated that the vascular supply to this mass originated from the intrahepatic portal vein (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea), confirming herniation of a portion of the liver into the thoracic cavity through a diaphragmatic defect (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb). Based on the collective imaging findings, the prenatal ultrasound diagnosis was established as: a retrosternal isoechoic mass, consistent with Morgagni hernia, accompanied by massive pericardial effusion. Fetal magnetic resonance imaging (MRI) also confirmed the herniation of a part of the liver (marked by an asterisk in the image) into the thoracic cavity along with a significant pericardial effusion (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea).\u003c/p\u003e \u003cp\u003eTo alleviate persistent compression of both lungs by the pericardial effusion and prevent further pulmonary hypoplasia, a pericardiocentesis was successfully performed in utero. Follow-up examination four weeks post-procedure showed improvement in lung compression and better lung expansion compared to prior findings. The pregnant woman delivered a male infant weighing 2400 g via cesarean section at 39⁺ weeks of gestation, with Apgar scores of 9 at 1 minute and 10 at 5 minutes. The newborn was transferred to our Neonatal Intensive Care Unit(NICU) on the same day and was placed on conventional mechanical ventilation via endotracheal intubation. A right-sided diaphragmatic hernia repair was performed on the second postnatal day. Intraoperative findings revealed an approximately 2 cm \u0026times; 2 cm defect in the anteromedial portion of the right diaphragm, through which part of the right hepatic lobe had herniated into the right thoracic cavity. A hernial sac and a distended pericardium were observed posterior to the sternum, with a portion of the pericardium forming the wall of the hernial sac. No significant fluid accumulation was noted upon incision. The newborn continued to receive ventilatory support postoperatively, with gradual improvement in respiratory status. Subsequent follow-up indicated a favorable recovery.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn prenatal ultrasound examination, Morgagni hernia typically manifests as herniation of the liver into the thoracic cavity through a diaphragmatic defect. As the condition progresses, it may gradually lead to pulmonary compression and pericardial effusion. In the present case, two-dimensional prenatal ultrasound identified the fetal diaphragmatic defect and abnormal liver position. Tracing the hernial orifice allowed for a preliminary assessment of the origin of the herniated contents. Three-dimensional imaging provided a more clearer visualization of the margins of the diaphragmatic defect and the anatomical relationship between the hernial sac and the diaphragm. This enhanced visualization contributes to improved diagnostic sensitivity and accuracy.\u003c/p\u003e \u003cp\u003eIn this case of Morgagni hernia accompanied by massive pericardial effusion, the precise underlying mechanism remains incompletely understood. Existing research suggests potential associations with the following hypotheses [4]: (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) obstruction of hepatic venous return leading to congestion and exudation; (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e) compression of the thoracic duct resulting in lymphatic accumulation. Although the pericardial effusion exerted posterior compression on both lungs, increasing the risk of pulmonary hypoplasia, the fetus in this case did not exhibit cardiac dysfunction or signs of cardiac tamponade. This may be attributed to the gradual accumulation of fluid, allowing for compensatory pericardial dilation. Therefore, the combined use of prenatal two-dimensional and three-dimensional ultrasonography enables more accurate identification of the diaphragmatic defect location, tracing of the origin of the herniated contents, and assessment of the spatial relationship between the effusion and lung tissue, all of which hold significant diagnostic value for this condition. Furthermore, pericardial effusion caused by Morgagni hernia must be differentiated from pleural effusion. The latter typically presents with bilateral lungs displaced centrally, floating within the accumulated fluid, whereas the former results in posterior compression of both lungs. This distinction is a critical diagnostic point and is closely related to subsequent clinical management strategies.\u003c/p\u003e \u003cp\u003eThe prognosis of this condition primarily depends on the developmental status of the lungs and heart. In this case, intrauterine pericardiocentesis performed at 27 weeks of gestation effectively alleviated pulmonary compression, and follow-up examinations demonstrated improved lung expansion. Following birth, the infant underwent surgical repair of the diaphragmatic hernia and recovered well, with subsequent follow-up yielding satisfactory outcomes. Therefore, accurate prenatal ultrasound diagnosis plays a crucial role in guiding perinatal management. Morgagni hernia should also be differentiated from the following conditions: Hiatal hernia typically appears on ultrasound as a diaphragmatic sac-like structure, which may exhibit gastric mucosal folds or air-fluid levels and maintains continuity with the sub-diaphragmatic stomach. Pulmonary sequestration, often presenting as a solid-cystic lesion in the posterior basal segment of the lower lobe, can be diagnosed by tracing its anomalous systemic arterial supply using three-dimensional ultrasound. Pericardial tumors manifest as an intracardiac or pericardial mass with an intact diaphragm and are frequently complicated by cardiac tamponade and fetal hydrops.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eCDH \u0026nbsp; \u0026nbsp; \u0026nbsp; Congenital Diaphragmatic Hernia\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMRI \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Magnetic Resonance Imaging\u003c/p\u003e\n\u003cp\u003eNICU \u0026nbsp; \u0026nbsp; \u0026nbsp; Neonatal Intensive Care Unit\u003c/p\u003e\n\u003cp\u003eH \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Heart\u003c/p\u003e\n\u003cp\u003eP \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Pericardial Effusion\u003c/p\u003e\n\u003cp\u003eL \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Liver\u003c/p\u003e\n\u003cp\u003eSP \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Spine\u003c/p\u003e\n\u003cp\u003eCM \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Centimeter\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMM \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Millimeter\u003c/p\u003e\n\u003cp\u003eG \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Gram\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors would like to express their gratitude to the patients and their families who participated in this study.We would also like to thank the medical and research staff at Gansu Maternal and Child Health Hospital for their support and assistance in conducting this research.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eI) Conception and design: T Pan,T Li; (II) Administrative support: B Ma, T Li; (III) Provision of study materials or patients: B Ma; (IV) Collection and assembly of data: T Pan, T Li,W Pang, G Wang; (V) Manuscript writing: All authors; (VI) Final approval of manuscript: All authors.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was supported by the Outstanding Talent Program (Grant No. GMCCH2025-2-2-02).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability :\u0026nbsp;\u003c/strong\u003enot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll procedures performed in this study were in accordance with the ethical standards of the Medical Ethics Committee of Gansu Provincial Maternity and Child-Care Hospital and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient\u0026rsquo;s next of kin for publication of this article and any accompanying images. A copy of the written consent is available for review by the editorial office of this journal.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe clinical data and imaging used in this study were obtained with the written informed consent of the legal guardians of the fetuses involved in the research. The consent covers the use of these materials for scientific research and publication purposes. All materials will be made freely available in accordance with the relevant Creative Commons license.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor details\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e1\u003c/sup\u003eUltrasound Medicine Center, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, People\u0026rsquo;s Republic of China.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical trial number\u003c/strong\u003e: not applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eLiu Y, Zhang Y, Ren X, et al. There were 2 cases of Morgagni hernia. Chin J Laparosc Surg (Electronic edition). 2018;11(4):245\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHaino K, Serikawa T, Itsukaichi M, et al. Morgagni hernia with massive pericardial effusion diagnosed in the second trimester: prenatal diagnosis and perinatal management. Fetal Diagn Ther. 2011;29(1):108\u0026ndash;10.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZamprakou A, Berg C, Strizek B, et al. Morgagni hernia presenting with massive pericardial effusion and ascites: prenatal management by thoraco-amniotic shunting and fetal endoscopic tracheal occlusion (FETO) and review of the literature. Arch Gynecol Obstet. 2016;294(5):953\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBabic I, Al-Jobair H, Al Towaijri O, et al. Prenatal Diagnosis and Management of a Rare Central Tendon Defect Type of Congenital Diaphragmatic Hernia with a Massive Pericardial Effusion. Case Rep Obstet Gynecol. 2020;2020:6798253.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXiaoqing G, Qin D, Hailang Y, Junhua L, Liang Q. One case of Morgagni hernia [J]. J Practical Radiol. 2022;38(9):1563\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"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":"bmc-pregnancy-and-childbirth","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"prch","sideBox":"Learn more about [BMC Pregnancy and Childbirth](http://bmcpregnancychildbirth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/prch/default.aspx","title":"BMC Pregnancy and Childbirth","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Morgagni hernia, Pericardial effusion, Prenatal, Three-dimensional ultrasound","lastPublishedDoi":"10.21203/rs.3.rs-8609285/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8609285/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis case report presents a rare instance of fetal Morgagni hernia. A 27-week pregnant woman was found to have a fetal Morgagni hernia during a routine prenatal examination. The condition likely resulted from a congenital defect in the diaphragm, characterized by failure of the retrosternal portion to close, leading to communication between the pericardial and peritoneal cavities. A portion of the liver herniated through this defect into the retrosternal region, compressing the pericardium and causing massive pericardial effusion, along with lung compression and subsequent pulmonary hypoplasia.\u003c/p\u003e","manuscriptTitle":"Prenatal Ultrasound Diagnosis of a Rare Morgagni Hernia: A Case Report","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-11 17:00:22","doi":"10.21203/rs.3.rs-8609285/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-03-05T19:19:28+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-04T06:50:11+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"140820897499121622738443384958201226977","date":"2026-02-26T07:43:21+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-18T20:42:17+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-17T04:37:02+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"109268437468317100833788651372559542746","date":"2026-02-17T01:31:30+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"270523198482429411679864413554207074885","date":"2026-02-11T12:02:47+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"281587884095907309298562926419774428920","date":"2026-02-09T19:17:27+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-02-09T11:35:32+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-01-19T05:29:27+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-01-16T07:44:53+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-01-16T07:41:50+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Pregnancy and Childbirth","date":"2026-01-15T09:51:10+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-pregnancy-and-childbirth","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"prch","sideBox":"Learn more about [BMC Pregnancy and Childbirth](http://bmcpregnancychildbirth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/prch/default.aspx","title":"BMC Pregnancy and Childbirth","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"1fc38730-d0e7-40dd-8296-9d6710bef80e","owner":[],"postedDate":"February 11th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-04-27T16:05:04+00:00","versionOfRecord":{"articleIdentity":"rs-8609285","link":"https://doi.org/10.1186/s12884-026-09119-9","journal":{"identity":"bmc-pregnancy-and-childbirth","isVorOnly":false,"title":"BMC Pregnancy and Childbirth"},"publishedOn":"2026-04-21 15:59:03","publishedOnDateReadable":"April 21st, 2026"},"versionCreatedAt":"2026-02-11 17:00:22","video":"","vorDoi":"10.1186/s12884-026-09119-9","vorDoiUrl":"https://doi.org/10.1186/s12884-026-09119-9","workflowStages":[]},"version":"v1","identity":"rs-8609285","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8609285","identity":"rs-8609285","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}