Research Article: Impact of prenatal screening on the prevalence of Down syndrome in Slovenia

Date Published: June 30, 2017

Publisher: Public Library of Science

Author(s): Gorazd Rudolf, Nataša Tul, Ivan Verdenik, Marija Volk, Anamarija Brezigar, Nadja Kokalj Vokač, Nataša Jeršin, Bernarda Prosenc, Tanja Premru Sršen, Borut Peterlin, Pal Bela Szecsi.


To evaluate the impact of prenatal screening and genetic testing for trisomy 21 (T21) on the prevalence of T21 in Slovenia.

Data about all prenatally and postnatally confirmed cases of T21 in Slovenia between 1981 and 2012 were collected retrospectively from all genetic laboratories in Slovenia. The expected number of babies with T21 according to maternal age was calculated.

The primary outcomes measures were number of fetuses and newborn infants with T21 diagnosed prenatally and postnatally and the impact of advances in screening and genetic diagnostics on the prevalence of newborns with T21 in Slovenia.

Despite a significantly increased mean maternal age from 25.4 years in year 1981 to 30.3 years in year 2012 the prevalence of newborn infants with T21 was 0.51 per 1000 births compared to 0.55 per 1000 births, respectively. The prevalence of prenatally diagnosed cases increased from 0.03 per 1000 births to 2.06 per 1000. The detection rate of T21 in year 2012 was 78,9%. The total number of prenatal invasive procedures (chorionic villous sampling and amniocenteses) carried out during that period was rising until 2002, since when it is stable at around 7%.

The advancement and implementation of screening tests and prenatal diagnostic procedures in Slovenia caused an important improvement in the efficiency of the prenatal detection of T21.

Partial Text

Down’s syndrome (T21) is the most common aneuploidy compatible with life and the most common cause of congenital developmental delay and represents an important public health challenge [1,2].

We collected all the prenatal and postnatal recorded cases of T21 confirmed by karyotyping for the period between 1981 and 2012 in Slovenia (S1 Table).

This study maps the changes in the prevalence of newborn infants with T21 with the advancement of prenatal diagnostic methods during the last 30 years in Slovenia.




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