ABSTRACT
Serendipitously for the development of human IVF, the human embryo exhibits a considerable degree of plasticity, enabling it to develop under a wide variety of culture conditions. The preimplantation human embryo is a highly dynamic entity which changes its needs as development proceeds. It is certainly the case that the human embryo can grow in absence of amino acids. Most culture media for the human embryo contain serum albumin as the protein source. Amino acids are increasingly used by human embryos as development proceeds, and by the blastocyst stage it produces around 25 pmol/embryo/h of ammonium which can accumulate in surrounding medium. Using culture media in a highly controlled environment, as detailed throughout this book, it is possible to attain high rates of human embryo development to the blastocyst stage. Further in-depth works on animal models, including the long-term follow-up of offspring, are therefore warranted before the addition of such factors to human embryo culture media can be considered safe.
