Background and objective: Down syndrome (DS) is the most frequent chromosomal abnormality and bears a severe associated morbidity. Our goal was to describe trends in the prevalence of DS in Asturias (Spain).
Material and methods: Data from the Registry of Congenital Defects were analyzed, including births and induced abortions, between 1990 and 2004.
Results: Out of a total 103 452 births, 356 chromosomal anomalies had been registered (176 births and 180 induced abortions) and there were 210 DS (119 live births, two stillbirths and 89 induced abortions). Total prevalence assessment showed an important upward trend over time in both cases. The prevalence of total chromosomal abnormalities increased from 22 cases per 10 000 births in 1990 to 48,6 in 2004 and the DS prevalence increased from 13 to 29,1. Furthermore, 63% of DS births presented one or more associated defects, cardiac and digestive tract defects being the most frequent.
Conclusions: Changes in maternal age and prenatal screening have influenced DS prevalence and trends.