The human embryo in vitro: recent progress

Abstract

This article reviews current laboratory techniques and procedures used for in vitro fertilization (IVF). The review covered relevant peer-reviewed articles in areas of IVF and associated treatment methods, such as embryo culture, intracytoplasmic sperm injection (ICSI), assisted hatching, cryopreservation and preimplantation genetic diagnosis and in vitro maturation. The availability of sequential media makes it possible to culture embryos to the later stage of blastocyst. The use of ICSI vs. IVF alone in male factor infertility results in the production of more embryos with a higher implantation rate. As a result, ICSI has been used successfully worldwide to treat infertile men to enable them to father children. Lack of standardized criteria for patient selection has complicated attempts to qualify the therapeutic value of assisted hatching. There is a general consensus, however, that assisted hatching can be performed in patients following repeated failed fertilization and older women to assist blastocyst hatching, the final stage before uterine implantation. Preimplantation genetic diagnosis is offered to both fertile and infertile couples who are at risk of passing genetic defects to their children. There are a few reports of successful human pregnancies following in vitro maturation of immature oocytes. Over the last 2 decades, IVF and associated treatment methods have been developed and greatly improved. The efficacies of these laboratory procedures need to be evaluated to determine if the procedures used have beneficial outcomes in clinical practice.