title: Fetal aneuploidy screening with cell-free DNA in late gestation.
abstract: OBJECTIVE
  The aim of this study was to evaluate clinical use of NIPT at gestational ages of 23 weeks and above.
  
  
  METHODS
  A cohort of 5579 clinical patients with singleton gestations of 23 weeks or greater submitting a blood sample for NIPT in an 18-month period were selected for this study. Clinical outcomes were requested for samples with NIPT results indicating fetal aneuploidy and compared with NIPT findings to confirm concordance or discordance.
  
  
  RESULTS
  A review of clinical indications revealed that a significantly (p < 0.0001) larger proportion of late-gestation samples indicated abnormal ultrasound findings with or without other indications, 6.2% and 42.1%, compared with early-gestation samples, 1.8% and 6.0%, respectively. Of 5372 reported late-gestation samples, 151 (2.8%) were reported as aneuploidy detected or suspected. In late-gestation samples, the overall observed positive predictive value (PPV) for NIPT was 64.7%, with an observed PPV of 100% in the subset of cases with multiple clinical indications including abnormal ultrasound findings.
  
  
  CONCLUSIONS
  NIPT is a highly accurate prenatal screening option for women after 23 weeks of gestation. Women who presented for NIPT in the latter stages of pregnancy more frequently specified clinical indications of abnormal ultrasound findings than women who entered screening earlier in pregnancy.
authors.affiliation: a Illumina, Inc. , Redwood City, CA , USA and.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Taneja
authors.affiliation: b Department of Obstetrics and Gynecology , Division of Maternal-Fetal Medicine, University of Minnesota , Minneapolis, MN , USA.
authors.forename: Tracy L
authors.initials: TL
authors.lastname: Prosen
authors.affiliation: a Illumina, Inc. , Redwood City, CA , USA and.
authors.forename: Eileen
authors.initials: E
authors.lastname: de Feo
authors.affiliation: a Illumina, Inc. , Redwood City, CA , USA and.
authors.forename: Kristina M
authors.initials: KM
authors.lastname: Kruglyak
authors.affiliation: a Illumina, Inc. , Redwood City, CA , USA and.
authors.forename: Meredith
authors.initials: M
authors.lastname: Halks-Miller
authors.affiliation: a Illumina, Inc. , Redwood City, CA , USA and.
authors.forename: Kirsten J
authors.initials: KJ
authors.lastname: Curnow
authors.affiliation: a Illumina, Inc. , Redwood City, CA , USA and.
authors.forename: Sucheta
authors.initials: S
authors.lastname: Bhatt
mesh_terms: D000293:Adolescent; D000328:Adult; D025063:Chromosome Disorders / Q000175:diagnosis* / Q000235:genetics; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics; D004247:DNA / Q000097:blood*; D004314:Down Syndrome / Q000175:diagnosis* / Q000235:genetics; D005260:Female; D005865:Gestational Age; D006801:Humans; D062145:Maternal Serum Screening Tests; D008875:Middle Aged; D011237:Predictive Value of Tests; D011247:Pregnancy; D011262:Pregnancy Trimester, Second / Q000097:blood*; D011263:Pregnancy Trimester, Third / Q000097:blood*; D012189:Retrospective Studies; D014314:Trisomy / Q000175:diagnosis* / Q000235:genetics; D000073839:Trisomy 13 Syndrome; D000073842:Trisomy 18 Syndrome; D016216:Ultrasonography, Prenatal; D055815:Young Adult
chemical_list: D004247:DNA
keywords: Chromosomal abnormalities; NIPT; positive predictive value; prenatal screening; third trimester