P16.05: the Influence of Chromosomal Microarray and NIPT on the Diagnostic Yield in 6,811 High‐risk Pregnancies Without Ultrasound Anomalies

Methods: On 3rd June 2016 Embase and PubMed databases were systematically searched for all relevant articles on prevalence of pathogenic submicroscopic CNVs in fetuses tested due to advanced maternal age or parental anxiety. Relevant full text articles were analysed and based on the extracted data the prevalence of submicroscopic CNVs was calculated. Results: Meta-analysis was conducted in a pooled cohort of 10,614 fetuses based on the 10 largest studies (N > 300) of a total of 19 relevant studies. In 0.84%, 95%CI [0.55%, 1.30%] of fetuses a submicroscopic pathogenic aberration was detected prenatally. The onset/penetrance of the submicroscopic findings was studied in 10,314 fetuses out of 8 papers that presented aberrant cases with all necessary details. The prevalence of early onset syndromic disorders due to a submicroscopic aberration was calculated to be 1:270, based on 0.37%, 95%CI [0.27%, 0.52%] cases where aberrations were specified. Conclusions: This systematic review shows that a significant proportion of fetuses in a general pregnant population carry a submicroscopic pathogenic CNV. Based on these figures all women should be informed on their individual risk for all pathogenic chromosome aberrations and not only for common trisomies.