Comparison Of Next-generation Sequencing And Array Comparative Genomic Hybridization For Preimplantation Genetic Screening

Objective: To investigate the effects of next-generation sequencing(NGS)screening on clinical pregnancy and implantation outcomes for PGS patients in comparison to array comparative genomic hybridization(a CGH)screening.Materials and Methods: 101 patients that underwent preimplantation genetic screening in our hospital from December,2011 to December,2016 were enrolled in this retrospective study.The cohort patients requested PGS due to advanced maternal age(AMA),recurrent pregnancy loss(RPL),repeated implantation failure(RIF).Only patients with the following characteristics were included:(1)≥ 1 cleavage stage embryo available for biopsy on day 3 or ≥1 blastocyst available for biopsy on day 5;(2)presence of both ovaries and normal uterine lining;(3)undergoing preimplantation genetic screening for their embryos.Exclusion criteria were as follows:(1)patients with developmental abnormalities of the female genital organs;(2)patients with severe endometriosis or endometrial factors related infertility;(3)patients with endocrine disorders,such as hyper and hypothyroidism;(4)patients with autoimmune disease,such as systemic lupus erythematosus(SLE).According to the different comprehensive chromosome screening technology,the patients were divided into two groups: 41 patients undergoing NGS-based PGS;and 60 patients undergoing array-CGH-based PGS.Patients in both groups underwent day-3 blastomerebiopsy or day-5/6 trophectoderm biopsy with PGS and euploid embryos transfer.The aneuploidy rate,implantation rate,clinical pregnancy rate were compared between the NGS group and the array-CGH group.Results: The aneuploidy rate of day-3 cleavage stage embryos did not differ significantly between NGS group and array-CGH group(66.67% vs.73.50%,p=0.495);and the aneuploidy rate of day-5/6 blastocysts did not differ significantly between NGS group and array-CGH group(47.20% vs.42.30%,p=0.496).NGS screening identified euploid blastocysts for transfer and resulted in similarly high implantation rates and clinical pregnancy rate for PGS patients compared to a CGH screening(61.50% vs.64.80%,p=0.763;63.60% vs.71.90%,p=0.472).The observed multiple pregnancy rate(21.40% vs.46.20%,p=0.105),ectopic pregnancy(0.00% vs.4.90%,p=0.400),clinical miscarriage rate(14.30% vs.22.00%,p=0.536),live birth rate(54.50% vs.52.60%,p=0.897)were also comparable between the NGS and array-CGH group.Conclusions: 1.In comparison to array-CGH-based PGS,the clinical pregnancy and implantation outcomes were comparable for NGS-based PGS patients.2.In comparison to array-CGH,NGS is more accurate in detecting small segmental structure abnormalities of the chromosomes;it also can detect mosaicism in multicellular samples.3.NGS-based PGS may offer several advantages to array-CGH including: sufficient resolution;higher coverage;increased dynamic range;automation of the sequencing library and lower cost.