#237 : The Application of Noninvasive Implantation Capability Screening (NICS®) Resulted in Improved Clinical Outcomes in Patients with Recurrent Pregnancy Loss or Repeated Implantation Failure

Background and Aims: Chromosomal abnormalities are frequently observed in early human embryos, particularly in patients experiencing repeated pregnancy loss (RPL) or repeated implantation failure (RIF). Although preimplantation genetic testing for aneuploidy (PGT-A) is a common technique for screening embryo ploidy, it comes with the risks associated with embryo biopsy. To address this issue, we developed the NICS assay, which evaluates embryos using spent culture medium (SCM) and thus reduces the risks associated with embryo biopsy. However, further evaluation is required to determine the clinical applicability of NICS for patients with RPL or RIF. Method: This retrospective cohort study analyzed 303 patients with RPL or RIF between July 2018 and May 2021. These patients underwent aneuploidy screening using the NICS assay and were thus categorized into the NICS group. The non-NICS group consisted of patients who received conventional morphology embryo transfer during the same period. Routine intracytoplasmic sperm injection (ICSI) was performed, and the embryos were placed in droplets. Approximately 30 [Formula: see text] L of blastocyst medium from each embryo was transferred into cell lysis buffer, followed by DNA library preparation using the ChromInst kit from Yikon Genomics. Results: In patients with RPL, the NICS group demonstrated significantly lower rates of miscarriage per frozen embryo transfer (FET) than the non-NICS group, 17.9% vs 42.6%. Furthermore, the NICS group exhibited significantly higher rates of ongoing pregnancies (40.7% vs 25.0%) and live births (38.9% vs 20.6%) compared to the non-NICS group. In the case of patients with RIF, the NICS group showed higher clinical pregnancy rates per FET compared to the non-NICS group. Specifically, the clinical pregnancy rates, 46.9% vs 28.7%. Conclusion: The present study demonstrates that the use of NICS for selecting euploid embryos can effectively reduce the incidence of miscarriage in patients experiencing RPL, as well as improve the clinical pregnancy rate in those experiencing RIF.