title: First-trimester maternal serum progesterone in aneuploid pregnancies.
abstract: BACKGROUND
  First-trimester maternal serum screening for Down syndrome (DS) can be improved by the use of additional serum markers. We examined whether progesterone (P), synthesized by placenta, might be a first-trimester maternal serum marker for fetal DS.
  
  
  METHODS
  P was quantified in first-trimester maternal serum from 42 DS, six trisomy 18 and two trisomy 13 pregnancies and 115 controls. Log-regression of P versus gestational age in days was used to convert P concentrations into multiples of the median (MoM).
  
  
  RESULTS
  The P concentrations in controls increased with gestational age (p = 9.5 x 10(-7)). The log10MoM P distribution in DS pregnancies was not significantly different from that in controls. However, from day 58-67, the log10MoM P was elevated in DS pregnancies (n = 10) with a mean (SD) of 0.1040 (0.0956), compared to a mean (SD) of - 0.0109 (0.1661) in controls (n = 24) (p = 0.05). Five out of six trisomy 18 and both trisomy 13 pregnancies had a P MoM < 1.
  
  
  CONCLUSIONS
  P is not a useful marker for DS in first trimester, except perhaps in a narrow gestational age window from day 58 to 67. P is a trisomy 18/13 marker.
authors.affiliation: Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark. mic@ssi.dk
authors.forename: Michael
authors.initials: M
authors.lastname: Christiansen
authors.forename: Tina Lindvig
authors.initials: TL
authors.lastname: Sørensen
authors.forename: Severin Olesen
authors.initials: SO
authors.lastname: Larsen
authors.forename: Bent
authors.initials: B
authors.lastname: Nørgaard-Pedersen
mesh_terms: D000328:Adult; D000782:Aneuploidy; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D004314:Down Syndrome / Q000097:blood / Q000175:diagnosis; D005260:Female; D006801:Humans; D009035:Mothers; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000235:genetics; D011261:Pregnancy Trimester, First / Q000097:blood*; D011296:Prenatal Diagnosis / Q000379:methods; D011374:Progesterone / Q000097:blood*
chemical_list: D015415:Biomarkers; D011374:Progesterone