title: Prenatal invasive testing: a 13-year single institution experience.
abstract: OBJECTIVE
  To analyze trends in screening and invasive prenatal diagnosis over a 13-year period in relation to changes in the national prenatal screening policy.
  
  
  METHODS
  Fetal karyotypes obtained following 11 045 prenatal invasive procedures between January 1999 and December 2011 were retrospectively reviewed. Referral indications were classified as medical and non-medical (anxiety). The number of tests per relevant chromosomal abnormalities (CA) detected in both groups adjusted for indication was calculated.
  
  
  RESULTS
  A total of 414 CA were detected (3.8%), 355 of which were considered clinically significant. The percentage of invasive procedures has declined from 49% to 12%, although cases referred by anxiety have increased from 22% to 55%. A total of 3129 invasive procedures did not have any medical indication (28%) and 13 relevant CA (0.42%) were found in this group. In this low-risk series, the index "number of invasive testing needed to detect 1 relevant CA" adjusted for indication was 241.
  
  
  CONCLUSIONS
  Changes in our national prenatal policy through this 13-year period show an increasing efficiency of prenatal detection of CA. However, despite the intensifying screening policies, low-risk pregnant women show a growing demand for prenatal invasive testing and a baseline risk for cytogenetic abnormality of 1/241.
authors.affiliation: Department of Obstetrics and Gynecology, Fetal Medicine Unit, Hospital Universitari Quirón Dexeus , Barcelona , Spain and.
authors.forename: Carmen
authors.initials: C
authors.lastname: Comas
authors.forename: Mónica
authors.initials: M
authors.lastname: Echevarria
authors.forename: Ignacio
authors.initials: I
authors.lastname: Rodríguez
authors.forename: Bernat
authors.initials: B
authors.lastname: Serra
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Cirigliano
mesh_terms: D000328:Adult; D000649:Amniocentesis / Q000706:statistics & numerical data; D000782:Aneuploidy; D015193:Chorionic Villi Sampling / Q000706:statistics & numerical data; D025063:Chromosome Disorders / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D005820:Genetic Testing; D006801:Humans; D015994:Incidence; D007621:Karyotyping; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods* / Q000706:statistics & numerical data; D012017:Referral and Consultation / Q000706:statistics & numerical data; D012189:Retrospective Studies
keywords: Audit; Down syndrome; chromosome abnormalities; karyotyping; screening