title: Detection of triploidy at 11-14 weeks' gestation: a cohort study of 198 000 pregnant women.
abstract: OBJECTIVE
  To assess the detection rate of triploidy at first-trimester screening for trisomy 21 and evaluate outcome in triploid pregnancies.
  
  
  METHODS
  From 2008 to 2011, 198 427 women with singleton pregnancies underwent first-trimester screening between 11 + 2 and 14 + 0 weeks' gestation. Screening parameters included nuchal translucency, maternal serum free β-human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A). In all triploid fetuses, these parameters were re-evaluated. Karyotypes were established by invasive testing (chorionic villus sampling or amniocentesis) or postabortem and obtained from the Danish Cytogenetic Central Register and the Danish Fetal Medicine Database.
  
  
  RESULTS
  A total of 30 triploid fetuses underwent first-trimester screening. Twenty-five were diagnosed as a result of abnormal first-trimester scan findings, a detection rate of 83.3%. Twenty-three fetuses were identified due to a high risk for trisomy 13, 18 or 21 and two fetuses due to structural abnormalities. The incidence of triploidy at first-trimester screening was 1:6614. A smaller crown-rump length than that estimated by date of last menstrual period was found in 95% of the fetuses with data available for evaluation. Eight fetuses had a larger biparietal diameter than expected for gestational age. Fetuses with a 69,XXX karyotype had significantly lower multiples of the median values for β-hCG and PAPP-A than did 69,XXY fetuses (P = 0.045 and P = 0.02 forβ-hCG and PAPP-A, respectively). No infants with triploidy were born in the study period. Among the triploid gestations detected on first-trimester screening, 20 (80.0%) women chose termination of pregnancy, four (16.0%) had spontaneous miscarriage and one (4.0%) was stillborn.
  
  
  CONCLUSIONS
  First-trimester screening for trisomy 21 also provides a high detection rate for triploidy.
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital Roskilde, Roskilde, Denmark.
authors.forename: L
authors.initials: L
authors.lastname: Engelbrechtsen
authors.forename: K
authors.initials: K
authors.lastname: Brøndum-Nielsen
authors.forename: C
authors.initials: C
authors.lastname: Ekelund
authors.forename: A
authors.initials: A
authors.lastname: Tabor
authors.forename: L
authors.initials: L
authors.lastname: Skibsted
mesh_terms: D000328:Adult; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood; D018568:Crown-Rump Length; D003718:Denmark; D004314:Down Syndrome / Q000175:diagnosis*; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis*; D005865:Gestational Age; D006801:Humans; D007621:Karyotyping; D048208:Nuchal Translucency Measurement; D011247:Pregnancy; D011256:Pregnancy Outcome; D011261:Pregnancy Trimester, First; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis; D057885:Triploidy; D055815:Young Adult
chemical_list: D018997:Chorionic Gonadotropin, beta Subunit, Human; D011266:Pregnancy-Associated Plasma Protein-A
keywords: abnormalities; first-trimester screening; outcome; parental origin; triploidy