[Evaluation of the association of a serum marker and second trimester ultrasonography for the screening of trisomy 21 in women of less than 38 years. Prospective study of 5,163 patients].
OBJECTIVE
Use of serum markers alone for trisomy 21 screening programs leads to a high rate of amniocentesis. Adding a second parameter (ultrasonography during the second trimester) might reduce this rate yet retain satisfactory sensitivity. This work was conducted to evaluate the pertinence of associating serum hCG level between 16 and 17 weeks gestation and morphological ultrasonography between 18 ans 20 weeks gestation.


METHODS
A prospective study was conducted in 5,163 pregnant women aged over 38 years. A morphological ultrasonography was performed in all patients whose hCG level > 1/150 indicated a risk. An amniocentesis was proposed if an anomaly was detected at ultrasonography.


RESULTS
Serum hCG was above the risk threshold retained in 11.9% of the patients and among these patients at least one anomaly was detected at ultrasonography in 12%. An amniocentesis was performed in 1.4% of all patients. The positive predictive value of the screening test was 20%.


CONCLUSIONS
Combining a serum marker and ultrasonography during the second trimester allows a reduction in the rate of amniocentesis compared with screening with serum markers alone. Sensitivity for detecting trisomy 21 remains satisfactory.
Lefebvre
G
G
Service de Gynécologie-Obstétrique, CHU Pitié-Salpêtrière, Paris.
Vauthier-Brouzes
D
D
Choukroun
J B
JB
Sebagh
E
E
Bernard
M
M
Brochet
C
C
Lesourd
S
S
Darbois
Y
Y
D000328:Adult; D000649:Amniocentesis; D015415:Biomarkers / Q000097:blood; D006063:Chorionic Gonadotropin / Q000097:blood*; D004314:Down Syndrome / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008423:Maternal Age; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D018566:Pregnancy, High-Risk; D011446:Prospective Studies; D012307:Risk Factors; D016216:Ultrasonography, Prenatal
D015415:Biomarkers; D006063:Chorionic Gonadotropin
Evaluation de l'association marqueur sérique et échographie du deuxième trimestre pour le dépistage de la trisomie 21 chez les femmes de moins de 38 ans. Etude prospective chez 5,163 patientes.