title: Non-invasive prenatal testing: impact on invasive prenatal diagnosis at a mainland Chinese tertiary medical center.
abstract: OBJECTIVE
  We describe the changes over a 4-year period in the number of diagnostic testing after the introduction of non-invasive prenatal testing (NIPT).
  
  
  METHODS
  The rate of NIPT as an indication in women who received amniocentesis, and the number of amniocentesis required for detection of one case with major aneuploidy were compared between a 1-year baseline period before the introduction of NIPT, and the 3 years following NIPT introduction.
  
  
  RESULTS
  A total of 7536 amniocentesis procedures were performed over the 4-year study period. During the baseline period of the year 2011, the number of invasive testing required for detection of one common trisomy was 57. During the first 2 years that NIPT was offered, NIPT averaged 1.7 percent of the total indications for amniocentesis, and the required number of invasive testing decreased to 30. With the increase of the percentage of NIPT during the 3rd year, the required number of invasive testing further decreased to 26.
  
  
  CONCLUSIONS
  After the clinical introduction of NIPT, invasive prenatal diagnostic testing had not decreased at a Chinese prenatal diagnostic unit, but a remarkably improved detection rate of major aneuploidies in diagnostic procedures was observed.
authors.affiliation: a Prenatal Diagnostic Center, Guangzhou Women and Children Medical Center Affiliated to Guangzhou Medical University , Guangzhou , China.
authors.forename: Dong-Zhi
authors.initials: DZ
authors.lastname: Li
authors.affiliation: a Prenatal Diagnostic Center, Guangzhou Women and Children Medical Center Affiliated to Guangzhou Medical University , Guangzhou , China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhen
authors.affiliation: a Prenatal Diagnostic Center, Guangzhou Women and Children Medical Center Affiliated to Guangzhou Medical University , Guangzhou , China.
authors.forename: Min
authors.initials: M
authors.lastname: Pan
authors.affiliation: a Prenatal Diagnostic Center, Guangzhou Women and Children Medical Center Affiliated to Guangzhou Medical University , Guangzhou , China.
authors.forename: Jin
authors.initials: J
authors.lastname: Han
authors.affiliation: a Prenatal Diagnostic Center, Guangzhou Women and Children Medical Center Affiliated to Guangzhou Medical University , Guangzhou , China.
authors.forename: Xin
authors.initials: X
authors.lastname: Yang
authors.affiliation: a Prenatal Diagnostic Center, Guangzhou Women and Children Medical Center Affiliated to Guangzhou Medical University , Guangzhou , China.
authors.forename: Yan-Mei
authors.initials: YM
authors.lastname: Ou
mesh_terms: D000328:Adult; D002681:China; D005260:Female; D062489:Health Impact Assessment; D006801:Humans; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000191:economics / Q000639:trends*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D062606:Tertiary Care Centers
keywords: Aneuploidy screening; cell-free fetal DNA; prenatal diagnosis; trisomy 21