Impact of antiphospholipid biology in maternal Down syndrome screening.
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.
Brochet
Christine
C
UF d'Oncobiochimie et Biochimie Prénatale, GH Pitié-Salpêtrière, AP-HP, Paris, France.
Morin
Nathalie
N
Coudert
Mathieu
M
Vauthier-Brouzes
Danièle
D
Costedoat-Chalumeau
Nathalie
N
Bernard
Maguy
M
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
D017152:Antibodies, Antiphospholipid