Prospective first-trimester screening for trisomy 21 in 30,564 pregnancies.
OBJECTIVE
This study was undertaken to evaluate the performance of a 1-stop clinic for first-trimester assessment of risk (OSCAR) for trisomy 21 by a combination of maternal age, fetal nuchal translucency (NT) thickness, and maternal serum-free ss- human chorionic gonadotrophin (hCG) and pregnancy-associated plasma protein-A (PAPP-A).


METHODS
OSCAR was carried out in 30,564 pregnancies at 11 to 13 + 6 weeks. Patient-specific risks for trisomy 21 and detection and false-positive rates were calculated.


RESULTS
The median maternal age was 34 (range 15-49) years. Chromosomal abnormalities were identified in 330 pregnancies, including 196 cases of trisomy 21. The estimated risk for trisomy 21 was 1 in 300 or greater in 7.5% of the normal pregnancies, in 93.4% of those with trisomy 21 and in 88.8% of those with other chromosomal defects.


CONCLUSIONS
The most effective method of screening for chromosomal defects is by first-trimester fetal NT and maternal serum biochemistry.
Avgidou
Kyriaki
K
Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.
Papageorghiou
Aris
A
Bindra
Renu
R
Spencer
Kevin
K
Nicolaides
Kypros H
KH
D000293:Adolescent; D000328:Adult; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood; D004314:Down Syndrome / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000453:epidemiology; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008131:London / Q000453:epidemiology; D008423:Maternal Age; D008875:Middle Aged; D009333:Neck / Q000000981:diagnostic imaging / Q000196:embryology; D011237:Predictive Value of Tests; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011266:Pregnancy-Associated Plasma Protein-A / Q000378:metabolism; D011296:Prenatal Diagnosis; D011446:Prospective Studies; D014463:Ultrasonography
D018997:Chorionic Gonadotropin, beta Subunit, Human; D011266:Pregnancy-Associated Plasma Protein-A