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Serum β-hCG measured only 80 IU/L, highlighting that miscarriage and fetal demise can produce false-negative qualitative tests due to lower or declining hCG levels. The report emphasizes maintaining diagnostic suspicion and using early imaging in atypical presentations.",{"@graph":14,"@context":73},[15,34,56],{"@type":16,"itemListElement":17},"BreadcrumbList",[18,23,27,31],{"item":19,"name":20,"@type":21,"position":22},"https://docshare.wps.com","Home","ListItem",1,{"item":24,"name":25,"@type":21,"position":26},"https://docshare.wps.com/document/","Document",2,{"item":28,"name":29,"@type":21,"position":30},"https://docshare.wps.com/document/healthcare/","Healthcare",3,{"item":32,"name":10,"@type":21,"position":33},"https://docshare.wps.com/document/unrecognised-second-trimester-pregnancy-with-fetal-demise-presenting-as-acute-abdomen-and-a-negative-pregnancy-test/432928/",4,{"url":32,"name":10,"@type":35,"image":36,"author":41,"headline":10,"publisher":44,"fileFormat":47,"inLanguage":8,"description":12,"dateModified":48,"datePublished":49,"encodingFormat":47,"isAccessibleForFree":50,"interactionStatistic":51},"DigitalDocument",{"url":37,"@type":38,"width":39,"height":40},"https://docshare.wps.com/thumbnails/unrecognised-second-trimester-pregnancy-with-fetal-demise-presenting-as-acute-abdomen-and-a-negative-pregnancy-test/432928.png","ImageObject",300,407,{"name":42,"@type":43},"pop out","Person",{"url":19,"name":45,"@type":46},"DocShare","Organization","application/pdf","2026-10-30","2026-09-29",true,{"@type":52,"interactionType":53,"userInteractionCount":55},"InteractionCounter",{"@type":54},"ViewAction",7,{"@type":57,"mainEntity":58},"FAQPage",[59,65,69],{"name":60,"@type":61,"acceptedAnswer":62},"Why can urine pregnancy tests be negative in second-trimester fetal demise?","Question",{"text":63,"@type":64},"In miscarriage or fetal demise, human chorionic gonadotropin may be lower than expected or decline, so qualitative urine tests can be falsely negative despite advanced gestation.","Answer",{"name":66,"@type":61,"acceptedAnswer":67},"What imaging findings confirmed the diagnosis in this case?",{"text":68,"@type":64},"CT revealed fetal bones within the uterus, and bedside transabdominal ultrasound showed an intrauterine fetus without detectable cardiac activity, with femur length corresponding to about 18 weeks.",{"name":70,"@type":61,"acceptedAnswer":71},"How was the patient managed after admission?",{"text":72,"@type":64},"The patient remained haemodynamically stable and experienced a spontaneous complete miscarriage the next morning without needing surgical intervention.","https://schema.org",{"og:url":32,"og:type":75,"og:title":10,"og:site_name":45,"og:description":12},"article",{"robots":77,"canonical":32},"index,follow",{"doc_id":79,"site_id":7},432928,1791100125,{"code":4,"msg":82,"data":83},"success",[84,88,92,96,101,106,109,114,119,122,126],{"id":22,"doc_module":4,"doc_module_name":25,"category_name":85,"show_sort_weight":86,"slug":87},"Story & Novel",90,"story-novel",{"id":26,"doc_module":4,"doc_module_name":25,"category_name":89,"show_sort_weight":90,"slug":91},"Literature",80,"literature",{"id":33,"doc_module":4,"doc_module_name":25,"category_name":93,"show_sort_weight":94,"slug":95},"Exam",70,"exam",{"id":97,"doc_module":4,"doc_module_name":25,"category_name":98,"show_sort_weight":99,"slug":100},5,"Comic",60,"comic",{"id":102,"doc_module":4,"doc_module_name":25,"category_name":103,"show_sort_weight":104,"slug":105},6,"Technology",50,"technology",{"id":55,"doc_module":4,"doc_module_name":25,"category_name":29,"show_sort_weight":107,"slug":108},40,"healthcare",{"id":110,"doc_module":4,"doc_module_name":25,"category_name":111,"show_sort_weight":112,"slug":113},8,"Research & Report",30,"research-report",{"id":115,"doc_module":4,"doc_module_name":25,"category_name":116,"show_sort_weight":117,"slug":118},9,"Religion & Spirituality",20,"religion-spirituality",{"id":117,"doc_module":4,"doc_module_name":25,"category_name":120,"show_sort_weight":117,"slug":121},"World Cup","world-cup",{"id":123,"doc_module":4,"doc_module_name":25,"category_name":124,"show_sort_weight":123,"slug":125},10,"Lifestyle","lifestyle",{"id":127,"doc_module":4,"doc_module_name":25,"category_name":128,"show_sort_weight":97,"slug":129},19,"General","general",{"code":4,"msg":82,"data":131},{"doc_id":79,"user_id":132,"nickname":42,"user_avatar":133,"doc_module":4,"category_id":55,"category_name":29,"doc_title":10,"doc_description":12,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":55,"is_deleted":4,"is_public":22,"is_downloadable":22,"audit_status":22,"page_count":30,"language":139,"language_code":8,"site_id":7,"html_lang":8,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":12,"update_tm":143,"read_time":110,"preview_page_count":4},962090760408,"https://ap-avatar.wpscdn.com/davatar_085a072bc5b1113ac321206ff7593b45","Review began 11/30/2025  \nReview ended 12/04/2025  \nPublished 12/05/2025  \n© Copyright 2025  \nDesouky. This is an open access article distributed under the terms of the Creative Commons Attribution License CC-BY 4.0. , which permits unrestricted use , distribution , and reproduction in any medium , provided the original author and source are credited.  \nDOI: 10.7759/cureus.98517  \nOpen Access Case Report  \nUnrecognised Second-Trimester Pregnancy With Fetal Demise Presenting as Acute Abdomen and a Negative Pregnancy Test  \nMarwa E. Desouky 1  \n1. Obstetrics and Gynaecology, Northampton General Hospital, Northampton, GBR Corresponding author: Marwa E. Desouky, [marwa.desouky@nhs.net](marwa.desouky@nhs.net)  \nAbstract  \nA woman in her early 20s presented with abdominal pain and a heavy period, unaware that she was 18 weeks pregnant. Despite a negative urine pregnancy test, imaging revealed intrauterine fetal demise. This rare case highlights the importance of maintaining clinical suspicion and performing early imaging, as pregnancy tests may yield false-negative results in cases of miscarriage and fetal demise. Human chorionic gonadotropin (hCG) is produced by the placenta, but when a pregnancy fails to develop normally, such as in miscarriage, hCG levels may be lower than expected or decline, leading to negative test results despite advanced gestation.  \nCategories: Obstetrics/Gynecology  \nKeywords: abdominal pain, fetal demise, intrauterine fetal demise, negative pregnancy test, unrecognised pregnancy, urine β-hcg  \nIntroduction  \nSecond-trimester fetal demise is typically associated with well-recognised clinical features such as cessation of fetal movements, abdominal distension, amenorrhoea, and persistently positive pregnancy tests. Pregnancy detection usually relies on the presence of β-human chorionic gonadotropin (β-hCG), which remains elevated throughout gestation. However, unrecognised or “cryptic” pregnancies pose a diagnostic challenge, particularly when patients continue to experience bleeding resembling menstruation or present with nonspecific symptoms, such as abdominal pain, leading clinicians to initially consider more common gynaecological conditions [1] .  \nAlthough uncommon, false-negative urine or serum β-hCG tests have been reported in the literature, even in cases of advanced pregnancy or trophoblastic disease. One well-documented cause is the “hook effect,” in which extremely high β-hCG concentrations saturate the antibodies in the immunoassay, preventing proper complex formation and resulting in a falsely negative result [2,3] . Case reports describe patients with complete molar pregnancies who had repeatedly negative urine pregnancy tests, with diagnosis only confirmed after quantitative serum β-hCG testing with dilution [3] . Another case involved an adolescent presenting with abdominal pain and bleeding with a negative urine test; subsequent evaluation revealed a molar pregnancy following serum β-hCG measurement and imaging [3] .  \nIn this report, we describe a 24-year-old woman who presented with abdominal pain and what she believed to be a heavy menstrual period, later found to have a second-trimester fetal demise despite repeatedly negative urine β-hCG testing. This case emphasises the need to maintain a broad differential diagnosis in reproductive-aged women presenting with abdominal pain or abnormal bleeding, even when qualitative pregnancy tests are negative, and highlights the limitations of urine β-hCG assays in atypical presentations [1,2] .  \nCase Presentation  \nA woman in her early 20s, P2, presented to the emergency department with heavy per vaginal bleeding and lower abdominal pain. Her obstetric history included two previous lower-segment caesarean sections, with no other significant medical or surgical history. She reported regular menstrual cycles and stated that she was on day 6 of what she believed to be her current menstrual period.  \nInitial investigations in the emergency departmen","cbCaigShGKSq5h6D","https://ap.wps.com/l/cbCaigShGKSq5h6D","pdf",1446352,"English","# Abstract\n# Introduction\n# Case Presentation\n# Discussion\n## Diagnostic challenges\n## Hormone testing limitations","[{\"question\":\"Why can urine pregnancy tests be negative in second-trimester fetal demise?\",\"answer\":\"In miscarriage or fetal demise, human chorionic gonadotropin may be lower than expected or decline, so qualitative urine tests can be falsely negative despite advanced gestation.\"},{\"question\":\"What imaging findings confirmed the diagnosis in this case?\",\"answer\":\"CT revealed fetal bones within the uterus, and bedside transabdominal ultrasound showed an intrauterine fetus without detectable cardiac activity, with femur length corresponding to about 18 weeks.\"},{\"question\":\"How was the patient managed after admission?\",\"answer\":\"The patient remained haemodynamically stable and experienced a spontaneous complete miscarriage the next morning without needing surgical intervention.\"}]","Unrecognised Second-Trimester Pregnancy With Fetal Demise Presenting as Acute Abdomen and a Negative Pregnancy Test | PDF",1790661954]