Early human embryo development

Abstract

The preimplantation period of early human embryo development, which lasts about a week, begins with the fertilized egg and leads to the formation of the blastocysf. The first three days of preimplantation development occur in the Fallopian tube; the remaining four in the uterus. Implantation takes a further week and is thus complete by about 14 days after fertilization. The ability to mimic the preimplantation stages of human embryo development in vitro has led to a variety of assisted conception techniques, to help the infertile and those couples at risk of conceiving children with severe genetic disorders. Related work may lead to the development of new forms of contraception. In the UK, research on human embryos is strictly regulated by a legal body, the Human Fertilisation and Embryology Authority (HFEA). Many of the considerations underlying the legislation administered by the HFEA were derived from the report of the ‘Warnock Committee’, Biological knowledge, played, and continues to play, a key role in influencing decisions in this area.