title: Cell-free DNA testing in the maternal blood in high-risk pregnancies after first-trimester combined screening.
abstract: OBJECTIVE
  The objective of this study was to investigate a strategy for clinical implementation of cell-free DNA (cfDNA) testing in high-risk pregnancies after first-trimester combined screening.
  
  
  METHODS
  In 259 singleton pregnancies undergoing invasive testing after first-trimester combined screening, a maternal blood sample was sent to the laboratory Natera for cfDNA testing using a single-nucleotide polymorphism-based methodology.
  
  
  RESULTS
  The cfDNA test provided a result in 249 (96.1%) pregnancies and, among these, identified as being at high risk 35 of 36 cases of trisomy 21, 13 of 13 with trisomy 18, five of five with trisomy 13 and three of four with sex chromosome aneuploidies. A policy of performing an invasive test in women with a combined risk of ≥1 in 10 or NT ≥4 mm and offering cfDNA testing to the remaining cases would detect all cases of trisomy 21, 18 or 13, 80% of sex aneuploidies and 62.5% of other defects and would avoid an invasive procedure in 82.4% of euploid fetuses.
  
  
  CONCLUSIONS
  In high-risk pregnancies after combined screening, a policy of selecting a subgroup for invasive testing and another for cfDNA testing would substantially reduce the number of invasive procedures and retain the ability to diagnose most of the observed aneuploidies.
authors.affiliation: Department of Obstetrics and Gynecology 'L. Mangiagalli', Fondazione IRCCS 'Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Persico
authors.affiliation: Department of Obstetrics and Gynecology 'L. Mangiagalli', Fondazione IRCCS 'Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Boito
authors.affiliation: Department of Obstetrics and Gynecology 'L. Mangiagalli', Fondazione IRCCS 'Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Benedetta
authors.initials: B
authors.lastname: Ischia
authors.affiliation: Fetal Medicine Unit, Palagi Hospital, Florence, Italy.
authors.forename: Adalgisa
authors.initials: A
authors.lastname: Cordisco
authors.affiliation: Fetal Medicine Unit, Di Venere and Sarcone Hospitals, Bari, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: De Robertis
authors.affiliation: Department of Obstetrics and Gynecology 'L. Mangiagalli', Fondazione IRCCS 'Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Isabella
authors.initials: I
authors.lastname: Fabietti
authors.affiliation: Fetal Medicine Unit, Palagi Hospital, Florence, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Periti
authors.affiliation: Fetal Medicine Unit, Di Venere and Sarcone Hospitals, Bari, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Volpe
authors.affiliation: Department of Obstetrics and Gynecology 'L. Mangiagalli', Fondazione IRCCS 'Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Fedele
authors.affiliation: Fetal Medicine Unit, Di Venere and Sarcone Hospitals, Bari, Italy.
authors.forename: Georgios
authors.initials: G
authors.lastname: Rembouskos
mesh_terms: D000328:Adult; D002474:Cell-Free System / Q000737:chemistry; D004247:DNA / Q000032:analysis*; D005260:Female; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D062145:Maternal Serum Screening Tests / Q000379:methods*; D008875:Middle Aged; D009035:Mothers; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000097:blood*; D018566:Pregnancy, High-Risk / Q000097:blood*; D011296:Prenatal Diagnosis / Q000379:methods; D014314:Trisomy / Q000175:diagnosis; D055815:Young Adult
chemical_list: D004247:DNA