Meeting the challenge of unclaimed cryopreserved embryos.

With the rise of efficient and highly effective embryo cryopreservation techniques, the modern in vitro fertilization laboratory has unintentionally become a long-term storage facility for embryos and gametes. One challenge posed by long-term storage is the issue of unclaimed, effectively abandoned, cryopreserved embryos whose owners cannot be identified or are unable to provide a dispositional decision. Given the nuanced nature of dealing with human tissue, no straightforward solutions for managing this novel scenario have prevailed. In this article, we discuss the problem faced by physicians, clinics, and patients alike when faced with unclaimed cryopreserved embryos. We also review strategies for proactive prevention and resolution of conflicts that may arise when making dispositional decisions.

The role of assisted reproductive technology in the management of recurrent pregnancy loss.

PURPOSE OF REVIEW: Description of genetic screening of preimplantation embryos as a means of reducing miscarriages in patients with recurrent pregnancy loss. RECENT FINDINGS: That the promise of preimplantation genetic screening (PGS) for ameliorating recurrent pregnancy loss has been fulfilled is controversial. An array of comparative studies has suggested a positive effect of PGS on implantation rate, but these have been balanced by studies showing no effect or a negative effect, highlighting the need for more rigorously designed studies and randomized controlled trials. Emerging technologies may provide more information from the embryo biopsies even as the mosaicism of the embryo and its implications for interpreting PGS data are recognized. SUMMARY: Through the screening of embryos for abnormality in chromosome number or structure and selecting only normal embryos for transfer, PGS was envisioned and applied as a therapeutic tool for improving implantation and live birth rates from in-vitro fertilization and providing a means of attenuating pregnancy loss in recurrent pregnancy loss patients. An array of reports on the effects of PGS on embryo implantation and live birth rates has been made since its introduction, showing, variously, increases, decreases or no changes in these parameters. Various factors may influence the efficacy of PGS, including the patient population to which it is applied, technical aspects such as embryo biopsy, the genetic analysis and embryo culture environment, the current limitation of the genetic analysis (a subset of, rather than all, the 24 chromosomes) and the mosaicism of the embryo and blastocyst. Collectively, these contribute to the challenge of optimizing PGS and understanding how the screening result reflects the ultimate genetic constitution of the conceptus. Emerging cytogenetic and molecular technologies such as comparative genomic hybridization and microarray analysis may provide a broader appraisal of the embryo for a more comprehensive evaluation of developmental potential and prognosis for live birth.