title: Clinical and cytogenetic results of a large series of amniocentesis cases from Turkey: report of 6124 cases.
abstract: OBJECTIVE
  The aim of this study was to document the clinical and cytogenetic results of a large series of amniocentesis (AS) cases from Turkey.
  
  
  METHODS
  Second-trimester amniocentesis cases performed in Suleymaniye Maternity Hospital for Research and Training between January 2007 and December 2011 were included.
  
  
  RESULTS
  During this period, 6124 AS were performed. Indications were increased risk in maternal serum screening (MSS) (56%), advanced maternal age (29%) and pathologic ultrasound finding (11.5%). Most frequent MSS abnormality was abnormal triple test result (58%). Overall culture success rate was 98.8%. Chromosomal abnormality was detected in 215 (3.6%) of the 6052 cytogenetic results (74.9% numerical, 25.1% structural). Most frequent numerical chromosomal abnormality was trisomy 21 (61.9%). Clinically insignificant polymorphisms were the most frequent structural changes (n = 571). Most frequent polymorphism was increase in heterochromatin region in the 1st chromosome (n = 158). Advanced maternal age had a positive predictive value of 5.2%. Among the MSS tests, the combined test had the highest positive predictive value (5.2%).
  
  
  CONCLUSIONS
  In our study, abnormal MSS (and among these, abnormal triple test result) was the most frequent indication for amniocentesis. Our overall culture success rate was 98.8%. Frequency of major chromosomal abnormality was 3.2% and trisomy 21 was the most frequent abnormality.
authors.affiliation: Department of Medical Genetics, Suleymaniye Maternity Hospital for Research and Training, Istanbul, Turkey.
authors.forename: Zeynep
authors.initials: Z
authors.lastname: Ocak
authors.forename: Tülay
authors.initials: T
authors.lastname: Özlü
authors.forename: Hasan Fehmi
authors.initials: HF
authors.lastname: Yazıcıoğlu
authors.forename: Osman
authors.initials: O
authors.lastname: Özyurt
authors.forename: Mehmet
authors.initials: M
authors.lastname: Aygün
mesh_terms: D000328:Adult; D000649:Amniocentesis; D000653:Amniotic Fluid / Q000166:cytology; D002478:Cells, Cultured; D002869:Chromosome Aberrations; D025063:Chromosome Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics / Q000473:pathology; D004314:Down Syndrome / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D005260:Female; D006771:Hospitals, Maternity; D006801:Humans; D015994:Incidence; D011110:Polymorphism, Genetic; D011237:Predictive Value of Tests; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D012189:Retrospective Studies; D012306:Risk; D014421:Turkey / Q000453:epidemiology
keywords: Down syndrome; amniocentesis; chromosomal abnormality; prenatal diagnosis