title: Serum triple-marker screening in in vitro fertilization and naturally conceived pregnancies.
abstract: OBJECTIVE
  To determine whether results of second-trimester maternal serum triple-marker screening for Down syndrome and open neural tube defects in singleton pregnancies conceived from in vitro fertilization (IVF) differ from those of pregnancies conceived spontaneously.
  
  
  METHODS
  The screen-positive rates and triple-marker levels of patients conceiving singleton pregnancies by IVF were compared to age-adjusted standards.
  
  
  RESULTS
  Sixty-nine singleton IVF pregnancies with maternal serum screening were identified. Twenty-one (30.4%) of the 69 IVF singleton pregnancies had a positive screen for Down syndrome compared with a 14.4% expected screen-positive rate for the maternal age distribution in our observed sample (P = .013). The screen-positive rate for open neural tube defects in the measured population was similar to anticipated values based on historic controls (5.8% in IVF patients versus 5.3% in the total population). The median levels of the triple markers were 0.95 multiples of the median (MoM) for alpha-fetoprotein (AFP), 0.90 MoM for unconjugated estriol (E3), and 1.22 MoM for hCG.
  
  
  CONCLUSIONS
  The increased hCG levels as well as the slightly lower AFP and unconjugated E3 levels may contribute to the higher Down syndrome screen-positive rate in this IVF singleton population. These results may be due to the number of embryos transferred, the maternal hormonal environment of the IVF process, or other factors. Pregnancies conceived by IVF may be twice as likely to have a positive maternal serum screening test. As additional data are collected, corrected standards should be determined.
authors.affiliation: Department of Obstetrics and Gynecology, Women & Infants' Hospital, Providence, Rhode Island, USA. gary_frishman@brown.edu
authors.forename: G N
authors.initials: GN
authors.lastname: Frishman
authors.forename: J A
authors.initials: JA
authors.lastname: Canick
authors.forename: J W
authors.initials: JW
authors.lastname: Hogan
authors.forename: R J
authors.initials: RJ
authors.lastname: Hackett
authors.forename: L H
authors.initials: LH
authors.lastname: Kellner
authors.forename: D N
authors.initials: DN
authors.lastname: Saller
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D006063:Chorionic Gonadotropin / Q000097:blood*; D004314:Down Syndrome / Q000175:diagnosis*; D004964:Estriol / Q000097:blood*; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D009436:Neural Tube Defects / Q000175:diagnosis*; D011247:Pregnancy / Q000097:blood*; D000509:alpha-Fetoproteins / Q000032:analysis*
chemical_list: D015415:Biomarkers; D006063:Chorionic Gonadotropin; D000509:alpha-Fetoproteins; D004964:Estriol