Pre-implantation genetic diagnosis and pre-implantation genetic screening: two years experience at a single center

OBJECTIVE: Indications for preimplantation genetic diagnosis (PGD)/preimplantation genetic screening (PGS) cycles and clinical outcomes were evaluated at CHA Gangnam Medical Center. METHODS: This is retrospective cohort study. All patients (n=336) who went through in vitro fertilization (IVF)-PGD/PGS cycles (n=486) between January 2014 and December 2015 were included in Fertility Center of CHA Gangnam Medical Center. Patients underwent IVF-PGD/PGS with 24-chromosome screening. Patients with euploid embryos had transfer of one or 2 embryos in a fresh cycle with any subsequent frozen embryo transfer (ET) cycle. Compared implantation, clinical pregnancy, ongoing pregnancy, and early abortion rates were the main outcome measures. RESULTS: The most common indication for PGD/PGS was recurrent spontaneous abortion (n=160). The chromosome rearrangement cases (n=116) included 24 Robertsonian translocations, 60 reciprocal translocations, 3 inversions, 2 deletions, 4 additions, and 23 mosaicisms. PGS cases rather than the PGD cases showed higher implantation rates (26.4% vs. 20.3%), ongoing pregnancy rates (19.5% vs. 16.4%), and clinical pregnancy rates (28.6% vs. 23.3%). Implantation rates (30.3% vs. 23.7%), clinical pregnancy rates (39.2% vs. 25.2%), and ongoing pregnancy rates (25.7% vs. 17.5%) were significant higher in the blastocyst evaluation group than cleavage stage evaluation group. CONCLUSION: This was the largest study of PGD/PGS for 2 years at a single center in Korea. The pregnancy outcomes of PGD cases are slightly lower than PGS cases. It was confirmed again that success rate of PGD/PGS is higher if biopsy was done at blastocyst than cleavage stage.