Aim: In this explorative study it should be evaluated how the introduction of non invasive first trimester diagnosis (nuchal translucency measurement, Combined Test, first trimester ultrasound screening) has influenced the indications and cytogenetic results of chorion villi samplings.
Materials and methods: Between 1989 and 2008 3337 pregnancies with CVS between 11 and 14 weeks of gestation were examined retrospectively. They were divided in two groups: CVS 1989 - 2001 before introduction of non invasive first trimester diagnosis (n = 1698) and CVS 2002 - 2008 after introducing non invasive testing at the end of 2001 (n = 1639). In both groups the indications for CVS (maternal age, sonographic findings, past history, maternal anxiety, and abnormal results of the Combined Test only in the second group) and the cytogenetic results were evaluated.
Results: In the first group (1989 - 2001, n = 1698) 85,6% (n = 1454) of all CVS were performed because of maternal age and only 3% (n = 51) due to sonographic findings. In the second group (2002 - 2008, n = 1639) there was a distinct increase of sonographic findings leading to CVS (33,9%, n = 555) with a clear decrease of maternal age to 37,9% (n = 621). Abnormal cytogenetic results were found in 10,5% (n = 172) in the second group, in the first group only in 4,5% (n = 76), respectively. The parameter with the highest rate of chromosomal disorders was fetal hydrops (66,1%), follwed by hygroma colli (48,2%), malformations (12,9%) and increased nuchal translucency (11,2%). Regarding maternal age alone the rate of abnormal chromosomes was 3,1%.
Conclusions: It could be shown that non invasive first trimester diagnosis has lead to a more specific indication for invasive fetal testing (sonographic findings 33,9 vs. 3%, maternal age 37,9 vs. 85,6%) with a higher rate of chromosomal disorder in this group (10,5 vs. 4,5%).
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