Effect of prenatal diagnosis on prevalence of live births with Down Syndrome in Tuscany (1992-2002)

Objective: To determine the effect of invasive prenatal diagnosis and triple test on the number of live births with Down Syndrome in Tuscany. Methods: In order to determine the trend on the number of live births with Down Syndrome, the periods before (1992-1995) and after (1996-2002) the introduction of the triple test were analysed separately (275,549 births). Statistically significant differences were analysed. Results: A 28.6% reduction in births with Down Syndrome was found in the first period and a 65.2% reduction in the second period with a maximum reduction of 76.2% in 2002. After the introduction of the triple test, an increase in the number of 35-year-old women undergoing voluntary terminations of pregnancy in comparison with women under 35 is noticed (a mean of 20.1 cases against 7.8 cases, p<0.05). Conclusions: The application of the triple test and of invasive prenatal diagnosis led to a reduction in the number of live births with Down Syndrome. © Copyright 2005, CIC Edizioni Internazionali, Rome.