2381/34832 J. K. Artley J. K. Artley Gene expression and cleavage arrest in the human embryo. University of Leicester 2015 IR content 2015-11-19 08:59:47 Thesis https://figshare.le.ac.uk/articles/thesis/Gene_expression_and_cleavage_arrest_in_the_human_embryo_/10192640 In vitro fertilisation and embryo transfer (IVF-ET) is now an accepted part of clinical practice for the treatment of infertility offering live birth rates in the region of 24% per cycle when three embryos are returned to the uterus However analysis of success in terms of the number of established conceptions per embryo returned reveals that only 10.9% of embryos transferred implant. Achieving improved success for IVP-ET, especially following the replacement of a single embryo in order to reduce the risk of multiple pregnancy is undoubtedly dependent on an improved understanding of the mechanisms that lead to embryonic failure.