Key Factors to Avoid Cancellation of Trophectoderm Biopsy for Preimplantation Genetic Screening

This study analyzed 1103 cycles of assisted reproductive technology underdoing either intracytoplasmic sperm injection (ICSI) only or ICSI with preimplantation genetic screening (ICSI+PGS). The primary objective was to find the key factors resulting in cancellation of ICSI+PGS cycles. The embryos were cultured in one step media to the blastocyst stage. The trophectoderm biopsies were performed on day-5 or day-6 and the embryos were vitrified. Upon receiving PGS results and availability of at least one euploid embryo, patients were prepared for frozen embryo transfer. The patients were grouped into ≤35, 36-39, 40-42, 43-46 and 47-48 yrs. Out of 1103 cycles, 826 cycles were in ICSI and 129 in ICSI+PGS group, from which 79 cases were cancelled. The cancellation rate increased with increase in the age category. The key factors for ICSI+PGS cycle cancellation were advanced female age and availability of <5 mature oocytes. Other reasons included poor oocyte quality, increased abnormal fertilization and availability of no motile sperm. The study proposes to optimize ovarian stimulation to retrieve about 15 oocytes per retrieval for a success ICSI+PGS cycle if trophectoderm biopsy is to be performed. In advanced age or poor responders, multiple retrievals may be needed to obtain enough blastocyst for PGS. The study highlights that counseling of patients undergoing ICSI+PGS should include not only success rates with PGS, but also information on the factors that may result in cycle cancellation. Therefore, prior to initiation of treatment it is essential to ensure that the patient has clearly understood the advantages and disadvantages of PGS and is prepared for all possible cycle outcomes.

Keywords: Trophectoderm biopsy, aneuploidy, preimplantation, PGS, PGD, PGT, ICSI.