Sequential screening for trisomy 21 by nuchal translucency measurement in the first trimester and maternal serum biochemistry in the second trimester in a low-risk population.
OBJECTIVE
To evaluate screening for trisomy 21 in a low-risk population utilizing a combination of nuchal translucency measurement in the first trimester and the triple test in the second trimester.


METHODS
This was a retrospective study of 9342 women with singleton pregnancies who booked for delivery in our hospital over a period of 5 years. A nuchal translucency scan was carried out at 10-13 weeks' gestation and for those with a measurement of 3.5 mm or more chorionic villus sampling was performed. All other women were asked to return for the triple test at 16 weeks' gestation. Amniocentesis was offered to women in whom the nuchal translucency was 2.5-3.4 mm, the triple test showed a risk of > or = 1 : 250 and in women aged > or = 35 years.


RESULTS
The detection rate using the combined screening method was 95% (18/19) with a screen-positive rate of 7.2%. In comparison, screening by maternal age alone would have identified nine (47%) trisomy 21 pregnancies with a screen-positive rate of 10.7%.


CONCLUSIONS
Our data suggest that the combination of nuchal translucency measurement in the first trimester and the triple test in the second trimester is associated with a very high detection rate of trisomy 21 at a relatively low screen-positive rate.
Schuchter
K
K
Department of Obstetrics and Gynecology, Ludwig Boltzmann Institute of Clinical Obstetrics and Gynecology, Danube Hospital, SMZO, Vienna, Austria. Katharina.Schuchter@smz.magwien.gv.at
Hafner
E
E
Stangl
G
G
Ogris
E
E
Philipp
K
K
D000293:Adolescent; D000328:Adult; D000649:Amniocentesis; D015415:Biomarkers / Q000097:blood; D004314:Down Syndrome / Q000175:diagnosis* / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D008423:Maternal Age; D008875:Middle Aged; D009333:Neck / Q000000981:diagnostic imaging* / Q000196:embryology*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D011863:Radioimmunoassay; D012189:Retrospective Studies; D018570:Risk Assessment; D016216:Ultrasonography, Prenatal
D015415:Biomarkers