title: Current practices in determining amnionicity and chorionicity in multiple gestations.
abstract: OBJECTIVE
  To evaluate the accuracy of amnionicity and chorionicity (A/C) diagnosis of referral physicians and a tertiary care center as compared to histopathologic diagnosis.
  
  
  METHODS
  A retrospective study of 289 multi-fetal gestations was performed comparing A/C diagnoses of referring physicians, a tertiary care center, and histopathology.
  
  
  RESULTS
  Two hundred and eighty-nine multi-fetal pregnancies were referred for evaluation; only 43.6% (126/289) carried an accurate diagnosis of A/C before tertiary care center evaluation. The tertiary care center accurately identified A/C in 94.8% (274/289) overall and 100% in first trimester twins and triplets. Referrals with an unspecified A/C diagnosis included 46.1% (113/245) twins and 64.1% (25/39) triplets.
  
  
  CONCLUSIONS
  Accurate diagnosis of A/C can be obtained by the early assessment of key sonographic findings. Referral providers are less accurate at determining A/C of multifetal gestation when compared to a tertiary center, suggesting that an emphasis should be placed on enhancing these diagnostic skills in the general community or encouraging referral when diagnosis is ambiguous.
authors.affiliation: Department of Reproductive Medicine, University of California, San Diego, Medical Center, 200 W. Arbor Drive, San Diego, CA 92103, USA.
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Wan
authors.forename: David
authors.initials: D
authors.lastname: Schrimmer
authors.forename: Véronique
authors.initials: V
authors.lastname: Taché
authors.forename: Kristen
authors.initials: K
authors.lastname: Quinn
authors.forename: D Yvette
authors.initials: DY
authors.lastname: Lacoursiere
authors.forename: Gina
authors.initials: G
authors.lastname: James
authors.forename: Kurt
authors.initials: K
authors.lastname: Benirschke
authors.forename: Dolores H
authors.initials: DH
authors.lastname: Pretorius
mesh_terms: D000293:Adolescent; D000328:Adult; D000650:Amnion / Q000000981:diagnostic imaging*; D002823:Chorion / Q000000981:diagnostic imaging*; D005260:Female; D005865:Gestational Age; D006801:Humans; D008875:Middle Aged; D011247:Pregnancy; D011272:Pregnancy, Multiple; D027724:Reproductive Techniques, Assisted; D012189:Retrospective Studies; D014310:Triplets; D014427:Twins; D016216:Ultrasonography, Prenatal / Q000639:trends*