title: Second-trimester maternal serum screening for Down syndrome in in vitro fertilization pregnancies.
abstract: OBJECTIVE
  To examine whether second-trimester maternal serum triple marker screening results differ between in vitro fertilization (IVF) pregnancies and naturally conceived pregnancies.
  
  
  METHODS
  Second-trimester maternal serum triple marker screening results from 88 IVF pregnancies were compared with 596 naturally conceived pregnancies (controls). Controls were matched to each IVF pregnancy by maternal age, gestational age and date of blood collection. All pregnancies in the study were known to have normal outcome. Multiple of the median (MoM) levels of human chorionic gonadotrophin (hCG), unconjugated estriol (uE3) and alpha-fetoprotein (AFP), and the false-positive rate for Down syndrome were compared between the two groups.
  
  
  RESULTS
  No statistically significant differences in analyte levels or in Down syndrome false-positive rate were observed between the IVF and naturally conceived pregnancies.
  
  
  CONCLUSIONS
  IVF patients can be counselled about maternal serum triple marker screening in the same manner as patients with naturally conceived pregnancies. There is no evidence to support the general use of analyte correction factors in the interpretation of second-trimester maternal serum screen results in IVF pregnancies.
authors.affiliation: Department of Medical Genetics, Children's and Women's Health Centre of British Columbia, Vancouver, BC, Canada.
authors.forename: Jennifer D
authors.initials: JD
authors.lastname: Rice
authors.forename: Sarah F
authors.initials: SF
authors.lastname: McIntosh
authors.forename: Anne C
authors.initials: AC
authors.lastname: Halstead
mesh_terms: D000328:Adult; D015415:Biomarkers; D006063:Chorionic Gonadotropin / Q000097:blood*; D004314:Down Syndrome / Q000097:blood* / Q000175:diagnosis*; D004964:Estriol / Q000097:blood*; D005260:Female; D005307:Fertilization in Vitro; D005315:Fetal Diseases / Q000175:diagnosis*; D006801:Humans; D008403:Mass Screening; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D000509:alpha-Fetoproteins / Q000032:analysis*
chemical_list: D015415:Biomarkers; D006063:Chorionic Gonadotropin; D000509:alpha-Fetoproteins; D004964:Estriol