Down syndrome in the Czech Republic during 1961-1997: prevalence, prenatal diagnosis and maternal-age-specific rates.
Data from a population-based register of congenital anomalies in the Czech Republic (total number of 5,319,002 births from the period under the study and 4933 Down syndrome cases) were used. Mean incidence of Down syndrome in births during the total period was 7.91/10,000 live births, the total incidence with the inclusion of prenatally diagnosed cases was 9.47/10,000 live births. The ratio of prenatally diagnosed cases out of the total number of Down syndrome cases increased in the period 1980-1997 from 20% to 60% in the whole population. The age distribution among mothers with Down syndrome babies shows a significantly increased risk for a maternal age of 34 years and over. The results indicate the important role of prenatal diagnosis in the change of incidence of Down syndrome at birth. Maternal age-specific rates must be used as basic data for improved calculation of individual risk in screening for Down syndrome in a population.
Sípek
A
A
Institute of Care of Mother and Child, Praha, Czech Republic. sipek@yahoo.com
Gregor
V
V
Horácek
J
J
Chudobová
M
M