634: The impact of preimplantation genetic screening (PGS) on prenatal diagnostic genetic testing in IVF pregnancies

Abstract

In recent years, cell-free DNA screening has significantly reduced the number of diagnostic genetic testing in pregnancy, an integral part of fellowship training in maternal-fetal medicine. Pre-implantation genetic screening (PGS) is commonly performed in IVF pregnancies, therefore we aimed to determine the impact of this screening test on subsequent diagnostic genetic testing with chorionic villus sampling (CVS) and amniocentesis. We performed a retrospective cohort study of patients undergoing IVF at a single center from January 2014 to December 2016. Multiple gestations were excluded. All patients underwent routine prenatal screening, including early and late anatomy sonograms, and diagnostic genetic testing at our institution. The rate of invasive diagnostic genetic testing was compared between patients with pregnancies achieved after transfer of a PGS-tested euploid embryo (i.e. study group, n = 37) and those with pregnancies achieved after transfer of untested embryo (i.e. controls, n = 27). Wilcoxon rank sum tests and Fisher's exact tests were employed for statistical analysis. Maternal age (p = 0.85), ethnicity (p = 0.72) and nuchal translucency measurements (p = 0.73) were similar between the two groups. Patients with non-PGS tested pregnancies had a higher BMI (mean 29.7, p = 0.01) than those with PGS-tested pregnancies. The rate of abnormal sonographic findings (p = 0.61), cell-free DNA testing (p = 0.32) and abnormal diagnostic genetic test results (p = 0.85) were similar between the two groups. Most importantly, there was no significant difference in the rate of diagnostic genetic testing with CVS or amniocentesis (12 vs. 8, p = 0.69) between the two groups. The implementation of PGS in IVF patients did not reduce the number of invasive diagnostic tests performed in our study population.