Belgium/epidemiology; Down Syndrome/diagnosis/epidemiology; Female; Humans; Incidence; Infant, Newborn; Mass Screening/methods; Maternal Age; Pregnancy; Pregnancy, High-Risk; Prenatal Diagnosis/methods; Statistics as Topic
Abstract :
[en] In South Belgium (Wallonia), the 'triple test' was introduced in 1990-1991, and is nowadays a widely accepted screening method for assessment of trisomy 21 risk in pregnancy. The 'triple test' is not regulated and can be freely performed by any biomedical lab, making epidemiological data unavailable. By contrast, cytogenetic investigations are limited to a few genetic centres, and accurate statistics can be easily built from their files. During the period 1984-1989, a total of 244 trisomy 21 (1/876 pregnancies) were diagnosed in the Genetic Centres of Liege and Loverval, 42 (17%) of them prenatally. During the period 1993-1998, 294 trisomy 21 (1/704 pregnancies) were observed, 165 (56%) of which prenatally, and more than 90% of affected pregnancies were terminated. Even after correction for late foetal loss of trisomic foetuses, the difference is highly significant, and corresponds to a theoretical shift in the incidence of trisomy 21 at birth from 1/794 to 1/1606. As no remarkable progress occurred in other non-invasive prenatal screening procedures or general health care policies in Belgium, the most reasonable explanation is the use on a large scale of triple test by pregnant women, and the election of termination for most affected pregnancies.
Disciplines :
Genetics & genetic processes
Author, co-author :
Verloes, Alain ; Université de Liège - ULiège > Génétique générale et humaine
Spencer K., Carpenter P. (1992) Risk of Down's syndrome and anmiocentesis rate. BMJ 304:640-641.
Verloes A., Schoos R., Koulischer L. (1992) Non-radioactive assay of AFP, hCG, and uE3 from dried blood specimens: A low-cost alternative for maternal screening for trisomy 21. Prenat Diagn 12:1073-1074.
Verloes A., Schoos R., Herens C., Vintens A., Koulischer L. (1995) A prenatal trisomy 21 screening program using alpha-fetoprotein, human chorionic gonadotropin, and free estriol assays on maternal dried blood. Am J Obstet Gynecol 72:167-174.
1996, 2.
Koulischer L., Gillerot Y. (1980) Down's syndrome in Wallonia (South Belgium), 1971-1978: Cytogenetics and incidence. Hum Genet 54:243-250.
Koulischer L., Gillerot Y., Lefèvre M., Lami M., Mancuso S. (1991) Down syndrome: Prenatal diagnosis and incidence at birth. A 20-year study in Belgium. Am J Hum Genet 49(SUPPL.):267.
Schreinemachers D.M., Cross P.K., Hook E.B. (1982) Rates of trisomies 21, 18, 13 and other chromosome abnormalities in about 20 000 prenatal studies compared with estimated rates in live births. Hum Genet 61(4):318-324.
Wald N.J., Kennard A., Hackshaw A., McGuire A. (1997) Antenatal screening for Down's syndrome. J Med Screen 4:181-246.