title: Additive effect of factors related to assisted conception on the reduction of maternal serum pregnancy-associated plasma protein A concentrations and the increased false-positive rates in first-trimester Down syndrome screening.
abstract: OBJECTIVE
  To analyze whether assisted conceptions need adjustments in first-trimester Down syndrome screening and why modifications in screening markers occur.
  
  
  METHODS
  Eleven-year cohort retrospective analysis.
  
  
  METHODS
  Maternal-fetal medicine unit.
  
  
  METHODS
  Two thousand eleven naturally conceived normal singleton pregnancies and 2,042 normal singleton pregnancies achieved with assisted conception: 350 by IUI and 1,692 with IVF (n = 328) or intracytoplasmic sperm injection (ICSI; n = 1,364), using nondonor (n = 1,086) or donated ova (n = 606), with fresh (n = 1,432) or frozen (n = 260) embryos.
  
  
  METHODS
  Comparison of ultrasound and biochemical markers of first-trimester Down syndrome screening according to the mode of conception and considering the clinical and laboratory parameters related.
  
  
  METHODS
  Nuchal translucency (NT), PAPP-A and free βhCG maternal serum concentrations, and false-positive rates (FPRs).
  
  
  RESULTS
  NT is unaffected by the mode of conception. Singleton pregnancies achieved by IVF and ICSI with nondonor oocytes have reduced maternal serum PAPP-A and increased FPR, which are significant only in ICSI cycles. Pregnancies from frozen embryos with hormone therapy also show decreased PAPP-A but without affecting the FPR. Elevated maternal serum fβhCG levels in oocyte donation do not influence the FPR.
  
  
  CONCLUSIONS
  Among assisted conceptions, only nondonor IVF/ICSI singleton pregnancies need adjustments of the maternal serum PAPP-A in first-trimester Down syndrome screening.
authors.affiliation: Instituto Valenciano de Infertilidad, Valencia, Spain; Departamento de Pediatría, Obstetricia y Ginecología, Facultad de Medicina, Universidad de Valencia, Valencia, Spain. Electronic address: Jose.Bellver@ivi.es.
authors.forename: José
authors.initials: J
authors.lastname: Bellver
authors.forename: Cristina
authors.initials: C
authors.lastname: Casanova
authors.forename: Nicolás
authors.initials: N
authors.lastname: Garrido
authors.forename: Coral
authors.initials: C
authors.lastname: Lara
authors.forename: José
authors.initials: J
authors.lastname: Remohí
authors.forename: Antonio
authors.initials: A
authors.lastname: Pellicer
authors.forename: Vicente
authors.initials: V
authors.lastname: Serra
mesh_terms: D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood; D004314:Down Syndrome / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging; D015536:Down-Regulation; D005189:False Positive Reactions; D005260:Female; D005307:Fertilization in Vitro / Q000009:adverse effects; D006801:Humans; D007315:Insemination, Artificial / Q000009:adverse effects; D048208:Nuchal Translucency Measurement; D018587:Oocyte Donation; D011237:Predictive Value of Tests; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000097:blood; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis*; D011296:Prenatal Diagnosis / Q000379:methods; D027724:Reproductive Techniques, Assisted / Q000009:adverse effects*; D012189:Retrospective Studies
chemical_list: D015415:Biomarkers; D018997:Chorionic Gonadotropin, beta Subunit, Human; D011266:Pregnancy-Associated Plasma Protein-A; C579283:PAPPA protein, human
keywords: First-trimester Down's syndrome screening; PAPP-A; assisted conception; false-positive rates; free βhCG