title: Serum free beta-HCG and alpha-fetoprotein levels in IVF, ICSI and frozen embryo transfer pregnancies in maternal mid-trimester serum screening for Down's syndrome.
abstract: BACKGROUND
  The aim of this study was to compare the maternal mid-trimester free beta-HCG and alpha-fetoprotein (AFP) levels in pregnancies conceived by assisted reproduction technology and spontaneous pregnancies in Down's syndrome screening. The influence of the number of embryos transferred and the amount of gonadotrophins used on the marker levels was also evaluated.
  
  
  METHODS
  The study population consisted of 58 IVF, 32 ICSI and 26 frozen embryo transfer (FET) singleton pregnancies. The levels of beta-HCG and AFP were compared with the control group of 6548 singleton spontaneous pregnancies.
  
  
  RESULTS
  The false positive rate (FPR) in the Down's syndrome screening was 19% overall in assisted reproductive technology pregnancies, being highest (30.8%) in the FET group. The free beta-HCG multiples of the median (MoM) values were statistically significantly elevated only in the FET group (1.33 MoM; P = 0.012). A positive correlation between the number of embryos transferred and the marker levels was observed in the IVF group. No correlation was found between the amount of gonadotrophin medication used and the marker levels.
  
  
  CONCLUSIONS
  The present data confirm that the overall FPR in the serum screening for Down's syndrome in assisted reproduction pregnancies is high, resulting in unnecessary invasive procedures.
authors.affiliation: Department of Obstetrics and Gynaecology, University of Turku, Kiinamyllynkatu 4-8, FIN-20520 Turku, Finland. raija.raty@pp.inet.fi
authors.forename: R
authors.initials: R
authors.lastname: Räty
authors.forename: A
authors.initials: A
authors.lastname: Virtanen
authors.forename: P
authors.initials: P
authors.lastname: Koskinen
authors.forename: L
authors.initials: L
authors.lastname: Anttila
authors.forename: J
authors.initials: J
authors.lastname: Forsström
authors.forename: P
authors.initials: P
authors.lastname: Laitinen
authors.forename: P
authors.initials: P
authors.lastname: Mörsky
authors.forename: A
authors.initials: A
authors.lastname: Tiitinen
authors.forename: U
authors.initials: U
authors.lastname: Ekblad
mesh_terms: D000328:Adult; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D015925:Cryopreservation; D004314:Down Syndrome / Q000175:diagnosis*; D004624:Embryo Transfer; D005189:False Positive Reactions; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D011247:Pregnancy / Q000097:blood*; D011262:Pregnancy Trimester, Second; D012099:Reproductive Techniques; D020554:Sperm Injections, Intracytoplasmic; D000509:alpha-Fetoproteins / Q000032:analysis*
chemical_list: D018997:Chorionic Gonadotropin, beta Subunit, Human; D000509:alpha-Fetoproteins