title: Diagnosing amnionicity at 6 weeks of pregnancy with transvaginal three-dimensional ultrasonography: case report.
abstract: OBJECTIVE
  To report a case of monochorionic, diamniotic twin pregnancy diagnosed at 6 weeks of pregnancy with three-dimensional (3D) transvaginal sonography and to discuss the use of this diagnostic method in the evaluation of multifetal pregnancy in the first trimester.
  
  
  METHODS
  Case report.
  
  
  METHODS
  University-based IVF program.
  
  
  METHODS
  A 30-year-old ovum recipient underwent ultrasonographic evaluation of a first-trimester twin pregnancy.
  
  
  METHODS
  Two-dimensional (2D) and 3D transvaginal sonography.
  
  
  METHODS
  Accurate diagnosis of chorionicity and amnionicity.
  
  
  RESULTS
  Monoamniotic pregnancy and conjoined twinning could not be ruled out by using 2D transvaginal sonography at 6 weeks, because only one yolk sac (YS) and no membranes could be visualized, and the two embryos were closely positioned within one gestational sac. Applying 3D technique, two YSs and two separate embryos could clearly be observed, establishing the correct diagnosis of a monochorionic, diamniotic pregnancy.
  
  
  CONCLUSIONS
  The 3D transvaginal ultrasonography provides a quick and accurate diagnostic modality for the evaluation of a first-trimester multiple gestation.
authors.affiliation: Department of Obstetrics, Gynecology and Reproductive Sciences, Mount Sinai School of Medicine, New York, New York 10029, USA.
authors.forename: A
authors.initials: A
authors.lastname: Babinszki
authors.forename: T
authors.initials: T
authors.lastname: Mukherjee
authors.forename: T
authors.initials: T
authors.lastname: Kerenyi
authors.forename: R L
authors.initials: RL
authors.lastname: Berkowitz
authors.forename: A B
authors.initials: AB
authors.lastname: Copperman
mesh_terms: D000328:Adult; D000650:Amnion / Q000000981:diagnostic imaging*; D002823:Chorion / Q000000981:diagnostic imaging*; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011272:Pregnancy, Multiple; D014427:Twins; D016216:Ultrasonography, Prenatal / Q000379:methods*