title: Impact of chorionicity on first-trimester nuchal translucency screening in ART twin pregnancies.
abstract: OBJECTIVE
  Nuchal translucency (NT) measurement in assisted reproduction treatment (ART) twins is less extensively investigated. Therefore, the present study compared NT measurements of spontaneously conceived twins with ART twins in dichorionic (DC) and monochorionic (MC) pregnancies.
  
  
  METHODS
  Retrospective analysis of 706 unaffected twins between 11 + 0 and 13 + 6 weeks conceived either spontaneously (n = 362) or with ART (n = 344). The group with spontaneous conception included 234 DC (64.6%) and 128 MC (35.4%) pregnancies. In the ART group, 326 were DC (94.7%) and 18 were MC (5.3%). NT values were transformed into multiples of median (MoM).
  
  
  RESULTS
  In the DC group, no significant differences between ART and spontaneously conceived twins (NT MoM 1.06 ± 0.28 vs 1.03 ± 0.29; p > 0.05) were observed. NT MoM of MC ART twins was higher compared with spontaneous MC twins (1.23 ± 0.82 vs 0.99 ± 0.27; p = 0.011). Although the incidence of twin-to-twin transfusion syndrome (TTTS) was higher among ART twins (11.1% vs 4.7%), inter-twin NT difference was similar between pregnancies with TTTS (0.42 ± 0.21) or without (0.40 ± 0.71).
  
  
  CONCLUSIONS
  Measurement of NT thickness in DC ART twins achieves comparable results with twins conceived spontaneously. Conclusions in MC twins are limited; however, higher NT MoM was not related to TTTS or selective intrauterine growth restriction.
authors: Department of Obstetrics and Prenatal Medicine, University Medical School Bonn, Bonn, Germany.
authors: A
authors: A
authors: Flöck
authors: J
authors: J
authors: Reinsberg
authors: C
authors: C
authors: Berg
authors: U
authors: U
authors: Gembruch
authors: A
authors: A
authors: Geipel
mesh_terms: D000328:Adult; D002823:Chorion / Q000000981:diagnostic imaging*; D005260:Female; D005330:Fetofetal Transfusion / Q000000981:diagnostic imaging / Q000453:epidemiology; D006801:Humans; D048208:Nuchal Translucency Measurement / Q000706:statistics & numerical data; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D059285:Pregnancy, Twin / Q000706:statistics & numerical data; D027724:Reproductive Techniques, Assisted / Q000706:statistics & numerical data; D012189:Retrospective Studies; D014429:Twins, Dizygotic / Q000706:statistics & numerical data; D014430:Twins, Monozygotic / Q000706:statistics & numerical data