title: First trimester screening for Down syndrome and assisted reproduction: no basis for concern.
abstract: In pregnancies obtained after assisted reproduction the false-positive rate of second trimester Down syndrome (DS) screening is increased by 1.5-3-fold. This may cause an increase in the number of amniocenteses and the fetal loss rate. The present study for the first time examined whether assisted reproductive technologies affect the results of first trimester screening. The markers PAPP-A, free beta-hCG and the nuchal translucency (NT) thickness were examined at 12-14 weeks' gestation. Screening markers in 47 in vitro fertilisation (IVF), 63 ovulation induction (OI) and 3026 spontaneously conceived singleton pregnancies were compared. The MoM (multiples of the median) value in the IVF pregnancies was 1.02 (95% CI: 0.85-1.22) for PAPP-A, 1.14 (95% CI: 0.95-1.37) for beta-hCG and 0.97 (95% CI: 0.89-1.05) for NT; the MoM value in the OI pregnancies was 0.89 (95% CI: 0.76-1.05) for PAPP-A, 1.08 (95% CI: 0.93-1.25) for beta-hCG and 1.02 (95% CI: 0.95-1.11) for NT. The first trimester marker values in assisted reproductive pregnancies and spontaneously conceived pregnancies were not significantly different. Estimated false-positive rates for a risk cut-off of 1:400 varied from 4.7% in IVF pregnancies to 5.1% in OI pregnancies. Therefore the false-positive rate in Down syndrome screening should be independent of the method of conception.
authors.affiliation: Department of Obstetrics and Gynaecology, Hvidovre Hospital, Copenhagen University, Copenhagen, Denmark.
authors.forename: K R
authors.initials: KR
authors.lastname: Wøjdemann
authors.forename: S O
authors.initials: SO
authors.lastname: Larsen
authors.forename: A
authors.initials: A
authors.lastname: Shalmi
authors.forename: K
authors.initials: K
authors.lastname: Sundberg
authors.forename: M
authors.initials: M
authors.lastname: Christiansen
authors.forename: A
authors.initials: A
authors.lastname: Tabor
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood; D004314:Down Syndrome / Q000175:diagnosis*; D005189:False Positive Reactions; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D009333:Neck / Q000000981:diagnostic imaging; D010062:Ovulation Induction; D011237:Predictive Value of Tests; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011266:Pregnancy-Associated Plasma Protein-A / Q000378:metabolism; D011296:Prenatal Diagnosis / Q000592:standards*; D011446:Prospective Studies; D014463:Ultrasonography
chemical_list: D018997:Chorionic Gonadotropin, beta Subunit, Human; D011266:Pregnancy-Associated Plasma Protein-A