Keep or toss? A retrospective evaluation of the benefits from culturing 0PN 1PB embryos zygotes after ∼18hrs post ICSI

Objective We examined embryo development potential and pregnancy outcomes from blastocysts that developed from 0PNpn, 1PB zygotes. Design A retrospective study in private IVF laboratory. Materials and Methods Over the course of twenty-four months, 68 blastocysts developed from mature oocytes that did not show visual signs of 2 pronuclei at approximently18hrs post-insemination by ICSI. The 0PN1PB embryos were cultured in Single Continuous Culture-NX (Irvine Scientific®) separately from the normally fertilized (2PN) zygote cohort and monitored accordingly. Any blastocysts obtained from 0PN1PB zygotes were either biopsied and/or frozen on day 5, 6 or 7 of embryo development. Results January 2017-December 2018, 68 blastocysts obtained from 0PN1PB zygotes represented approximately 1% of the total number of embryos cultured in our laboratory. Of the 68 blastocysts, 51were biopsied and subsequently tested by NexGen sequencing resulting in 23 (45%) of which were deemed euploid. 12 embryo transfers with euploid embryos were performed (11 frozen, 1 fresh) resulting in 5 (42%) with positive clinical pregnancies and 3 live births. Positive clinical pregnancy was defined cardiac activity visualized via ultrasound at 7 weeks gestation. The frequency of chromosomes that were chromosomally abnormal as indicated by PGT-A was also retrospectively evaluated which resulted in no correlation of a particular set of chromosomes Conclusion The result of 0PN1PB after ICSI is an artifact of every IVF program. The inefficiency of these embryos to develop into a blastocyst is well known. While the population of embryos produced from 0PN1PBs is considerably low, the minimal extra work and monitoring required does not outweigh the potential benefits of culturing these embryos to the blastocyst stage. Although our study numbers are small, this retrospective observation indicates that these embryos do have the potential to develop into a chromosomally normal blastocyst which can result in a live birth. Embryo transfer data is further limited by preference in selecting embryos which have resulted from 2PN zygotes versus those from 0PN1PB zygotes. However, by utilizing PGT-A technology, our study further validates that these embryos have similar euploid outcomes compared to those blastocysts which have developed from 2PN zygotes. With proper embryo culture organization, these embryos can be monitored effortlessly and become part of any IVF routine. Funding None Disclosures None