Aim: Preimplantation genetic screening (PGS) is a routine procedure performed in many in vitro fertilization (IVF) clinics. Embryo biopsy is an invasive procedure, and it has long been recognised that this procedure can affect the subsequent growth and development of the embryo.
Materials and methods: In total, 38 cycles from 31 couples were included in this study. Day 3 biopsy was performed on 126 embryos of 18 patients; 20 patients chose day 4 biopsy with 150 embryos tested. All specimens were screened on a 24-chromosome comparative genomic hybridization (CGH) array.
Results: Of the embryos subjected to day 3 and day 4 biopsies, 22.2% (28/126) and 28.7% (43/150) were normal, demonstrating that our biopsy system has no obvious detrimental effect on compaction. Embryos were transferred on the mornings of day 4 and day 5. Compared with day 3 biopsy (4/13; 30.8%), the day 4 biopsy (7/16; 43.8%) procedure provides an improved pregnancy rate with embryo transfer in current IVF cycle.
Conclusions: We suggest that biopsy performance on day 4, to obtain genetic materials without compromising embryo viability, shows promise for successful PGS in IVF.