title: When are amniotic fluid viral PCR studies indicated in prenatal diagnosis?
abstract: OBJECTIVE
  To determine which prenatal ultrasound findings indicate the need to also obtain PCR studies for viral genome in women undergoing midtrimester amniocentesis.
  
  
  METHODS
  This was a retrospective observational study on women that underwent amniotic fluid karyotyping and viral PCR testing for history or ultrasound based indication. Amniotic fluid was tested for adenovirus, cytomegalovirus, respiratory syncytial virus, enterovirus, Epstein-Barr virus, and parvovirus B19 using multiplex PCR study with multiple appropriate controls. Ultrasound findings were coded as normal or abnormal with 34 categories of ultrasound abnormality stratified into 18 subgroups. Relationships between these subgroups and karyotype/PCR results were tested by Pearson chi-square method or Fisher's exact test and overall logistic regression analysis.
  
  
  RESULTS
  Amniotic fluid samples from 1191 patients were obtained for the study. Abnormal karyotype was detected in 5.4% of cases (64/1191), and PCR was positive in 6.5% of cases (77/1191). Abnormal fetal ultrasonographic findings were observed in 28.4% of cases (338/1191). There was an association between intrauterine growth restriction, nonimmune hydrops fetalis, hand/foot anomalies or neural tube defects (NTDs), and PCR positivity. NTDs were associated with PCR positivity in fetuses with normal karyotype and nuchal thickening, cardiac or ventral wall defects were specifically associated with aneuploidy.
  
  
  CONCLUSIONS
  Amniotic fluid viral PCR testing should be considered for fetuses with intrauterine growth restriction, nonimmune hydrops fetalis, hand/foot anomalies, or NTDs. After aneuploidy is excluded, NTDs are associated with PCR positivity.
authors.affiliation: Center for Advanced Fetal Care, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD, USA.
authors.forename: L L
authors.initials: LL
authors.lastname: Adams
authors.forename: S
authors.initials: S
authors.lastname: Gungor
authors.forename: S
authors.initials: S
authors.lastname: Turan
authors.forename: J N
authors.initials: JN
authors.lastname: Kopelman
authors.forename: C R
authors.initials: CR
authors.lastname: Harman
authors.forename: A A
authors.initials: AA
authors.lastname: Baschat
mesh_terms: D000328:Adult; D000649:Amniocentesis / Q000379:methods*; D000653:Amniotic Fluid / Q000821:virology*; D015331:Cohort Studies; D004266:DNA Virus Infections / Q000175:diagnosis; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis*; D005865:Gestational Age; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods*; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000175:diagnosis*; D012327:RNA Virus Infections / Q000175:diagnosis; D012189:Retrospective Studies; D014777:Virus Diseases / Q000175:diagnosis*; D014780:Viruses / Q000235:genetics / Q000302:isolation & purification