title: Impact of antiphospholipid biology in maternal Down syndrome screening.
abstract: OBJECTIVE
  Women with antiphospholipid (aPL) biology present obstetric complications. The alpha-fetoprotein (AFP) serum levels of these patients are higher than in general population. Because AFP is involved in the calculation of the risk of trisomy 21 (T21), we studied the effect of AFP variations in the presence of aPL during T21 screening.
  
  
  METHODS
  The study group (aPL group) was comprised of 64 pregnancies in women with aPL antibodies. The control group was comprised of 21 655 pregnancies included in the national program for routine Down syndrome (DS) screening by maternal serum markers [human chorionic gonadotrophin (hCG) and AFP] between 14 + 0 and 18 + 6 weeks of gestation.
  
  
  RESULTS
  AFP values, converted in logarithm of multiples of the median (MoM), were significantly higher in the aPL group (0.03 vs 0.10; p = 0.018). After a matricial transformation of AFP MoM and hCG MoM in the aPL group, new T21 risks presented a median of one in 1665 versus one in 2574 (p < 0.0001 with a rank-sign test).
  
  
  CONCLUSIONS
  Our results highlight the fact that in the presence of aPL antibodies, the calculated risk of T21 is underestimated. Therefore, clinicians should interpret the screening borderline results in aPL patients with caution.
authors.affiliation: UF d'Oncobiochimie et Biochimie Prénatale, GH Pitié-Salpêtrière, AP-HP, Paris, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Brochet
authors.forename: Nathalie
authors.initials: N
authors.lastname: Morin
authors.forename: Mathieu
authors.initials: M
authors.lastname: Coudert
authors.forename: Danièle
authors.initials: D
authors.lastname: Vauthier-Brouzes
authors.forename: Nathalie
authors.initials: N
authors.lastname: Costedoat-Chalumeau
authors.forename: Maguy
authors.initials: M
authors.lastname: Bernard
mesh_terms: D000328:Adult; D017152:Antibodies, Antiphospholipid / Q000097:blood / Q000502:physiology*; D016736:Antiphospholipid Syndrome / Q000097:blood / Q000150:complications; D016022:Case-Control Studies; D015331:Cohort Studies; D004314:Down Syndrome / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D006801:Humans; D009035:Mothers; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D011256:Pregnancy Outcome; D011296:Prenatal Diagnosis / Q000379:methods; D012307:Risk Factors; D012680:Sensitivity and Specificity
chemical_list: D017152:Antibodies, Antiphospholipid