title: Noninvasive prenatal testing: more caution in counseling is needed in high risk pregnancies with ultrasound abnormalities.
abstract: OBJECTIVE
  Non-invasive prenatal testing (NIPT) is increasingly being used in prenatal aneuploidy screening. The objective of this study was to assess the positive predictive value in our cohort of 68 cases with positive NIPT result. In addition, we wondered if the use of NIPT in cases with ultrasound abnormalities is appropriate, given the limited number of chromosomes investigated.
  
  
  METHODS
  We performed confirmative invasive testing using karyotyping, fluorescence in situ hybridization (FISH) and/or high-resolution chromosomal microarray analysis.
  
  
  RESULTS
  In line with the published data, the positive NIPT result was confirmed in 64.7% of cases. Inconclusive and negative NIPT results followed by cytogenetically pathologic findings were encountered in three and in five cases, respectively. Four of the five fetuses with negative NIPT but pathologic cytogenetic findings were born with several malformations and diagnosed right after birth with severe genetic conditions. Of note, in all of those four cases, NIPT was offered despite the finding of major fetal ultrasound abnormalities and despite the fact that the family would not have opposed invasive testing or pregnancy termination.
  
  
  CONCLUSIONS
  More education of health care providers and caution in counseling and interpretation of test results are needed in order to meet the challenges that this new test, which enriches our diagnostic options in prenatal testing, poses.
authors.affiliation: Institute of Medical Genetics, University of Zurich, Zurich, Switzerland. Electronic address: oneda@medgen.uzh.ch.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Oneda
authors.affiliation: Institute of Medical Genetics, University of Zurich, Zurich, Switzerland.
authors.forename: Katharina
authors.initials: K
authors.lastname: Steindl
authors.affiliation: Institute of Medical Genetics, University of Zurich, Zurich, Switzerland.
authors.forename: Rahim
authors.initials: R
authors.lastname: Masood
authors.affiliation: Institute of Medical Genetics, University of Zurich, Zurich, Switzerland.
authors.forename: Irina
authors.initials: I
authors.lastname: Reshetnikova
authors.affiliation: Institute of Medical Genetics, University of Zurich, Zurich, Switzerland.
authors.forename: Pavel
authors.initials: P
authors.lastname: Krejci
authors.affiliation: Institute of Medical Genetics, University of Zurich, Zurich, Switzerland.
authors.forename: Rosa
authors.initials: R
authors.lastname: Baldinger
authors.affiliation: Institute of Medical Genetics, University of Zurich, Zurich, Switzerland.
authors.forename: Regina
authors.initials: R
authors.lastname: Reissmann
authors.affiliation: Institute of Medical Genetics, University of Zurich, Zurich, Switzerland.
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Taralczak
authors.affiliation: Institute of Medical Genetics, University of Zurich, Zurich, Switzerland.
authors.forename: Adriano
authors.initials: A
authors.lastname: Guetg
authors.affiliation: Division of Obstetrics, University Hospital Zurich, Zurich 8091, Switzerland.
authors.forename: Josef
authors.initials: J
authors.lastname: Wisser
authors.affiliation: Division of Neonatology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Fauchère
authors.affiliation: Institute of Medical Genetics, University of Zurich, Zurich, Switzerland.
authors.forename: Anita
authors.initials: A
authors.lastname: Rauch
mesh_terms: D000782:Aneuploidy; D000013:Congenital Abnormalities / Q000175:diagnosis / Q000235:genetics; D020732:Cytogenetic Analysis; D004314:Down Syndrome / Q000175:diagnosis; D005260:Female; D005317:Fetal Growth Retardation / Q000175:diagnosis; D005817:Genetic Counseling; D005865:Gestational Age; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007231:Infant, Newborn; D007621:Karyotyping; D008423:Maternal Age; D048208:Nuchal Translucency Measurement; D020411:Oligonucleotide Array Sequence Analysis; D011247:Pregnancy; D018566:Pregnancy, High-Risk; D011296:Prenatal Diagnosis / Q000379:methods*; D014314:Trisomy; D016216:Ultrasonography, Prenatal
keywords: Counseling; High-risk pregnancy; NIPT; Non-invasive prenatal testing; Positive predictive value