title: Maternal serum levels of placental proteins after in vitro fertilisation and their implications for prenatal screening.
abstract: OBJECTIVE
  To determine whether the serum levels of pregnancy-associated plasma protein A (PAPP-A), pregnancy-specific beta(1)-glycoprotein (SP1), placental lactogen (hPL) and human chorionic gonadotrophin (hCG) are different in pregnancies obtained after in vitro fertilisation (IVF) and embryo transfer (ET) in comparison to spontaneous pregnancies. Assessment of the need to establish normal medians for biochemical trisomy screening in IVF pregnancies.
  
  
  METHODS
  The population comprised 96 IVF-ET pregnancies, of which 79 came from fresh gonadotrophin-stimulated cycles and 17 from embryo transfers without gonadotrophin stimulation (natural cycle IVF, frozen embryo transfers), and 156 spontaneous pregnancies. A single blood sample was obtained between 7 + 0 and 16 + 3 weeks. PAPP-A, SP1, hPL and hCG were quantified and the levels compared between gonadotrophin-stimulated IVF, steroid-only- or non-stimulated IVF, and controls with respect to gestational age using non-parametric statistical analysis.
  
  
  RESULTS
  PAPP-A and hPL levels were reduced after stimulated IVF in early gestation (before 10 pregnancy weeks); SP1 followed the same trend without reaching statistical significance. hCG tended to be increased after IVF treatment including non-gonadotrophin-stimulation cycles, and also beyond 10 pregnancy weeks.
  
  
  CONCLUSIONS
  Reduced PAPP-A with increased hCG yields an increased risk in screening for foetal trisomy 21. We confirm recently published observations but do not recommend the establishment of normal medians for IVF pregnancies since the extent of the deviations is varying according to the different stimulation protocols and dosages of gonadotrophins used.
authors.affiliation: University Department of Obstetrics and Gynaecology, Berne, Switzerland. nick.bersinger@dkf.unibe.ch
authors.forename: N A
authors.initials: NA
authors.lastname: Bersinger
authors.forename: D
authors.initials: D
authors.lastname: Wunder
authors.forename: F
authors.initials: F
authors.lastname: Vanderlick
authors.forename: A
authors.initials: A
authors.lastname: Chanson
authors.forename: G
authors.initials: G
authors.lastname: Pescia
authors.forename: P
authors.initials: P
authors.lastname: Janecek
authors.forename: E
authors.initials: E
authors.lastname: Boillat
authors.forename: M H
authors.initials: MH
authors.lastname: Birkhäuser
mesh_terms: D000328:Adult; D006063:Chorionic Gonadotropin / Q000097:blood*; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D005865:Gestational Age; D006801:Humans; D008423:Maternal Age; D010928:Placental Lactogen / Q000097:blood*; D011247:Pregnancy; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis*; D011268:Pregnancy-Specific beta 1-Glycoproteins / Q000032:analysis*; D011296:Prenatal Diagnosis; D020554:Sperm Injections, Intracytoplasmic; D014314:Trisomy / Q000175:diagnosis
chemical_list: D006063:Chorionic Gonadotropin; D011268:Pregnancy-Specific beta 1-Glycoproteins; D010928:Placental Lactogen; D011266:Pregnancy-Associated Plasma Protein-A