The reduced use of invasive procedures leads to a change of frequencies of prenatally detected chromosomal aberrations: population data from the years 2012-2016.

Objective: The aim of the study was to analyze the results of screening for chromosomal aberrations in a population with a high rate of first-trimester screening and low rate of cell-free DNA testing.

Methods: The data were obtained from the National Registry of Congenital Anomalies of the Czech Republic. We calculated and compared the proportion of autosomal trisomies (Down, Edwards, and Patau syndrome) and of other chromosomal aberrations identified during prenatal diagnostics.

Results: We identified 3009 prenatally diagnosed cases of chromosomal aberrations in the 2012-2016 period. The number of major autosomal trisomies has increased from 329 cases (30.86 per 10,000 live births) in 2012 to 423 cases (37.41) in 2016 ( = 0.014). The numbers of other aberrations decreased from 246 cases (23.07 per 10,000) in 2012 to 217 cases (19.19) in 2016 ( = 0.017). The usage of invasive diagnostic procedures decreased from 1099.54 in 2012 to 622.73 in 2016 (per 10,000 live births).

Conclusions: Our population-based study confirmed a decrease in prenatal detection of nonmajor chromosomal aberrations wherein a decrease of invasive testing occurred. With the introduction of cell-free DNA testing, further decrease of invasive procedures and detection of nonmajor aberrations may be expected.