Question 1253
{"accessible":false,"alternatives":[{"id":6273,"text":"concordant gender"},{"id":6272,"text":"entangled cords"},{"id":6269,"text":"non-visualization of an inter-twin membrane"},{"id":6271,"text":"single placental mass"},{"id":6270,"text":"single yolk sac"}],"archived":false,"correctAlternativeId":6272,"explanation":"\u003cp\u003eThe finding of entangled umbilical cords is definitive for a monochorionic monoamniotic (MCMA) twin pregnancy.\u003c/p\u003e\u003cp\u003eAn intertwin membrane is absent in an MCMA pregnancy, however false non-visualization of the membrane may occur, particularly in very early first trimester\u0026nbsp;or late\u0026nbsp;pregnancy.\u003c/p\u003e\u003cp\u003eA single yolk sac was once thought to be a reliable sign of monoamniotic pregnancy.\u0026nbsp; Recent studies have demonstrated that two yolk sacs are seen in MCMA in approximately 1/3rd of cases.\u0026nbsp; Yolk sac number should not be used to define amnionicity.\u003c/p\u003e\u003cp\u003eA single placental mass may be seen\u0026nbsp;with either mono- or di-amniotic dichorionic pregnancies.\u0026nbsp;Further, two adacent placentas in a dichorionic pregnancy may also falsely appear as a single placental mass. The number of placental masses should not be used to determine amnionicity/chorionicity.\u003c/p\u003e\u003cp\u003eConcordant gender may be seen in any subtype of twin pregnancy.\u003c/p\u003e","id":1253,"imageUrl":null,"imageAttribution":null,"imageAttributionCaseInfo":null,"firstQuestionPath":"/questions/2175","nextQuestionPath":null,"relatedArticles":[{"id":14570,"title":"Umbilical cord entanglement","link":"/articles/umbilical-cord-entanglement?lang=us"},{"id":1696,"title":"Twin pregnancy","link":"/articles/twin-pregnancy-1?lang=us"}],"alsoUsedIn":[{"id":982,"kind":"Course","title":"2021 Virtual Conference Private Use - page 982","link":"https://radiopaedia.org/courses/2021-virtual-conference-private-use/pages/982"},{"id":982,"kind":"Course","title":"Radiopaedia 2021 - isoCME - page 982","link":"https://radiopaedia.org/courses/radiopaedia-2021-isocme/pages/982"},{"id":982,"kind":"Course","title":"2022 Virtual Conference Private Use - page 982","link":"https://radiopaedia.org/courses/2022-virtual-conference-private-use/pages/982"},{"id":970,"kind":"RestrictedPage","title":"Page 970 (in no courses)","link":"https://radiopaedia.org/admin/restricted_pages/970"},{"id":955,"kind":"RestrictedPage","title":"Page 955 (in no courses)","link":"https://radiopaedia.org/admin/restricted_pages/955"},{"id":1,"kind":"LiveSchedule","title":"1","link":"https://radiopaedia.org/admin/live_schedules/1"},{"id":17,"kind":"LiveSchedule","title":"17","link":"https://radiopaedia.org/admin/live_schedules/17"},{"id":431,"kind":"Course","title":"Radiology Review Course - Melbourne - page 431","link":"https://radiopaedia.org/courses/radiology-review-course-melbourne-2019/pages/431"},{"id":431,"kind":"Course","title":"Radiology Review Course - Melbourne - page 431","link":"https://radiopaedia.org/courses/radiology-review-course-melbourne-2020/pages/431"},{"id":431,"kind":"Course","title":"Radiology Review Course - page 431","link":"https://radiopaedia.org/courses/radiology-review-course-online/pages/431"},{"id":642,"kind":"Course","title":"Lectures by Alexandra Stanislavsky - page 642","link":"https://radiopaedia.org/courses/lectures-by-alexandra-stanislavsky/pages/642"},{"id":642,"kind":"Course","title":"Radiopaedia 2020 - Lectures Only - page 642","link":"https://radiopaedia.org/courses/radiopaedia-2020-exclusive/pages/642"},{"id":642,"kind":"Course","title":"Obstetrics \u0026 Gynaecology Lectures - page 642","link":"https://radiopaedia.org/courses/obgyn-lectures/pages/642"},{"id":642,"kind":"Course","title":"2020 Virtual Conference Private Use - page 642","link":"https://radiopaedia.org/courses/2020-virtual-conference-private-use/pages/642"},{"id":894,"kind":"Course","title":"2021 Virtual Conference Private Use - page 894","link":"https://radiopaedia.org/courses/2021-virtual-conference-private-use/pages/894"},{"id":894,"kind":"Course","title":"Radiopaedia 2021 - isoCME - page 894","link":"https://radiopaedia.org/courses/radiopaedia-2021-isocme/pages/894"},{"id":894,"kind":"Course","title":"Obstetrics \u0026 Gynaecology Lectures - page 894","link":"https://radiopaedia.org/courses/obgyn-lectures/pages/894"}],"stem":"\u003cp\u003eWhich of the following is diagnostic of a monochorionic monoamniotic twin pregnancy?\u003c/p\u003e","menuLinks":[{"text":"Report problem with question","url":"https://docs.google.com/forms/d/e/1FAIpQLSfO3soWYhOjJ7yErSysyCe5V4A1CqW7WK3rDA7MtAkecMGqNw/viewform?entry.1624461248\u0026entry.553583435=https://radiopaedia.org/questions/1253"}],"attemptsPercentages":[{"alternativeId":"6273","percentage":5},{"alternativeId":"6270","percentage":13},{"alternativeId":"6271","percentage":6},{"alternativeId":"6272","percentage":65},{"alternativeId":"6269","percentage":12}],"promptToLogin":false,"questionManager":false,"articleId":"monochorionic-monoamniotic-twin-pregnancy"}