Surveillance of final outcome of in vitro fertilization using pre-implantation genetic screening in Sri Lanka: an observational study

Abstract

INTRODUCTION AND OBJECTIVES: Chromosome abnormalities are well-established as one of the major factors for failed implantation in in-vitro fertilization (IVF) treatment. Pre-implantation genetic screening (PGS) as a method for assessing embryo's karyotype has been used in screening chromosome aneuploidies. It is increasingly being utilized in IVF centres worldwide. Since the first introduction of PGS in 1990, PGS has evolved from PCR based technique to FISH (Fluorescent In-Situ Hybridization) to finally Next Generation Sequencing (NGS) base platform. IVF has been available in Sri Lanka since the late 1990’s; however, commercial PGS services have only become available as recently as January 2018.Therefore, the objective of this study was to evaluate the chromosomal aneuploidies of IVF embryos sent for PGS analysis by a single IVF centre and to co-relate euploid embryos with their clinical pregnancies.METHODS: Embryos were biopsied at the blastocyst stage in WISH Fertility and IVF Clinic at the 3rd day of post fertilization. One to ten cells were isolated, washed and prepared for screening using the Ion ReproSeqTM PGM kit according to manufacturer’s instructions. DNA from each embryo was barcoded and then sequenced on the IonTM Personal Genome Machine using 316 chip. Sequencing data generated was analyzed using Ion ReporterTM software. Retrospective study was carried out in all embryos sent for PGS analysis at the Credence Genomics Pvt. Ltd. diagnostic laboratory between January 2018 and May 2018. Outcome information was collected from the WISH Fertility and IVF Clinic following embryo transfer. RESULTS: A total of 101 embryos were screened for chromosomal abnormalities prior to implantation. Thirty two embryos were found to have no aneuploidies and were suitable for implantation. Of the 32 normal embryos 23 embryos have been transferred to date. Clinical pregnancies were reported from 12 transferred embryos, giving a success rate of approximately 52.17% (12/23).CONCLUSION: It is widely reported that the conventional success rate for IVF ranges from 20-45% depending on the mother's age. As viability of embryos depends heavily on chromosomal copy number and stability, the use of PGS leads to an increase in success rate. As shown in this study, PGS is commercially available in Sri Lanka and can increase success rate for implantation up to 52%.