A Review of Non-invasive and Invasive Embryo Characteristics to Indentify the Most Competent Embryo for Transfer
Dirk Kotze *
Jones Institute, Norfolk, Virginia, USA.
Thinus F. Kruger
Department of Obstetrics and Gynaecology, Tygerberg Hospital and Stellenbosch University, Tygerberg, South Africa.
Geoffrey Sher
University of Nevada, School of Medicine (USA); Executive Medical Director: Sher Institute for Reproductive Medicine, Las Vagas, USA.
S. Oehninger
Department of Obstetrics and Gynecology; Director, The Jones Institute for Reproductive Medicine | EVMS Medical Group; 601 Colley Avenue, Norfolk, VA 23507-2007, USA.
*Author to whom correspondence should be addressed.
Abstract
Identifying “competent embryos” (those with the greatest potential to develop into normal concept) for transfer to the uterus has been a matter of the highest priority and the subject of both hot debate and ongoing research, since the very inception of human in vitro fertilization (IVF). A thorough literature search was performed to evaluate the correlation between pronuclear morphology, early embryo cleavage speed, cleavage stage embryos, embryo/blastocyst development, “omics”, sHLA-G expression, PGS, and implantation/pregnancy-generating potential in ART. Based on available literature, an array/combination of laboratory observations could assist the scientist with embryo selection. The pronuclear stage morphology, the early embryo division, cleavage embryo stage and quality of the day 3 embryos provides limited guidance. We conclude that use of (invasive) PGS in specific patient populations is appropriate; however, more data are needed to determine its true value for overall impact in ART. Non-invasive selection of blastocysts on day 5 with optimal sHLA-G expression provides a very high degree of confidence to yield a viable pregnancy and potentially reduce multiple gestations.
Keywords: Morphology, omics, soluble human leu kocyte antigen-G (sHLA-G), blastocyst, cytogenetics.