title: The introduction of the absolute risk for the detection of fetal aneuploidies in the first-trimester screening.
abstract: OBJECTIVE
  Maternal age is a crucial factor in fetal aneuploidy screening, resulting in an increased rate of false-positive cases in older women and false-negative cases in younger women. The absolute risk (AR) is the simplest way to eliminate the background maternal age risk, as it represents the amount of improvement of the combined risk from the maternal background risk. The aim of this work is to assess the performance of the AR in the combined first-trimester screening for aneuploidies.
  
  
  METHODS
  A retrospective validation of the AR in the combined first-trimester screening for fetal aneuploidies, in an unselected population at Altamedica Fetal-Maternal Medical Center in Rome, between March 2007 and December 2008.
  
  
  RESULTS
  Of 3845 women included in the study, we had a complete follow-up on 2984. We evaluated that an AR < 3 would individuate 22 of 23 cases of aneuploidy with a detection rate of 95.7% (95%CI 87.3-100), a false-positive rate of 8.7% (95%CI 7.7-9.7) and a false-negative rate of 4.3% (95%CI 0-12.7).
  
  
  CONCLUSIONS
  In our study, the AR ameliorates the detection rate for aneuploidy. Further research and a prospective study on a larger population would help us to improve the AR in detecting most cases of aneuploidy.
authors.affiliation: a Department of Prenatal Diagnosis , Altamedica Fetal-Maternal Medical Centre , Rome , Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Padula
authors.affiliation: b Department of Human Pathology in Adulthood and Childhood "G. Barresi" , Unit of Gynecology and Obstetrics, University of Messina , Messina , Italy.
authors.forename: Antonio Simone
authors.initials: AS
authors.lastname: Laganà
authors.affiliation: b Department of Human Pathology in Adulthood and Childhood "G. Barresi" , Unit of Gynecology and Obstetrics, University of Messina , Messina , Italy.
authors.forename: Salvatore Giovanni
authors.initials: SG
authors.lastname: Vitale
authors.affiliation: a Department of Prenatal Diagnosis , Altamedica Fetal-Maternal Medical Centre , Rome , Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: D'Emidio
authors.affiliation: a Department of Prenatal Diagnosis , Altamedica Fetal-Maternal Medical Centre , Rome , Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Coco
authors.affiliation: c Scientific Direction, Biostatistical Unit, Regina Elena Cancer Institute , Rome , Italy.
authors.forename: Diana
authors.initials: D
authors.lastname: Giannarelli
authors.affiliation: d Department of General Surgery and Medical Surgical Specialties , University of Catania , Catania , Italy , and.
authors.forename: Maria
authors.initials: M
authors.lastname: Cariola
authors.affiliation: e Department of Obstetrics and Gynecology , University of Perugia , Perugia , Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Favilli
authors.affiliation: a Department of Prenatal Diagnosis , Altamedica Fetal-Maternal Medical Centre , Rome , Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Giorlandino
mesh_terms: D000328:Adult; D000782:Aneuploidy; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood; D004314:Down Syndrome / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D008423:Maternal Age; D048208:Nuchal Translucency Measurement; D011237:Predictive Value of Tests; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult
chemical_list: D018997:Chorionic Gonadotropin, beta Subunit, Human
keywords: Absolute risk; Down syndrome; aneuploidy; first trimester screening; nuchal translucency