Authors: David Hill, PhD, Brian Su, MD and Gary Andrews. Beverly Hills, California
Purpose: To provide further evidence that day three biopsied human embryos can survive cryopreservation at later stages of development and lead to healthy pregnancies.
Rationale: The performance of preimplantation genetic testing (PGT) of day 3 embryos often requires mailing fixed blastomeres or polar bodies to “specialty” centers for evaluation. Reports on the genetic status of the biopsied embryos arrive back at the originating clinic about two days later via phone or fax. Under this arrangement, biopsied embryos are kept in extended culture until day 5-6.
Once the report detailing the genetic status of the embryos is received, embryo transfer or cryopreservation of embryos deemed “normal” can proceed. In this article we report a successful outcome (delivered twins) from thawed embryos biopsied at the 8-10 cell stage on culture day 3, then cryopreserved on culture day 6 as hatching blastocysts.
Methods: Standard techniques of ovulation induction, oocyte retrieval and in vitro fertilization and culture were employed on a 38 year old, G3P1022 woman to produce several day 3 embryos suitable for embryo biopsy / screen for aneuploidy by fluorescent in situ hybridization (FISH).
Due to clinically obvious hyperstimulation syndrome, three chromosomally balanced embryos were cryopreserved on day 6 using routine blastocyst freezing protocols, then thawed and transferred four months later.
Results: The patient delivered healthy, non-identical twin girls at term.
Conclusions: Biopsied human embryos can be successfully cryopreserved at later stages of development, and is a valid alternative to fresh embryo transfer under suboptimal or potentially dangerous conditions.