This chapter addresses issues related to patient selection and preparation prior to undergoing assisted reproductive technology (ART) techniques, and the role of regulatory control in ART and welfare of the child assessment. It discusses the special aspects of ART including gamete and embryo donation, pre-implantation genetic screening (PGS) and diagnosis (PGD) and fertility preservation. Before the processing of patient gametes or embryos, the couple should be screened for hepatitis B, hepatitis C and HIV to assess their risk of cross-contamination. In the UK, the regulatory control of ART lies with the Human Fertilisation and Embryology Authority (HFEA). The risk of implantation failure and pregnancy loss secondary to aneuploidy increases with advanced maternal age, particularly after the age of 35 years. Fertility preservation described in the chapter includes sperm cryopreservation, oocyte cryopreservation, and ovarian tissue cryopreservation.

Human reproduction appears to be an inefficient process, primarily because of chromosome errors in gametes and the resultant embryos. This chapter discusses the cytogenetic factors involved in miscarriage in the general population and in couples with recurrent pregnancy loss. It reviews the process of meiosis in gametogenesis and highlights the importance and limitations of cytogenetic analyses of miscarriage tissue. Recently, recurrent aneuploidy has been suggested as a factor associated with a history of recurrent pregnancy loss. Cytogenetic analyses can be performed on miscarriage tissue using several techniques, including cell culture followed by chromosome banding, microsatellite testing and comparative genomic hybridization. Comparative genomic hybridization followed by flow cytometry may prove a powerful technique to provide chromosome results on paraffin-stored miscarriage tissue. The possibility of recurring chromosome errors as etiologic for recurring pregnancy loss, has led to the recent application of pre-implantation genetic screening (PGS) for management of idiopathic recurrent miscarriage.

Pre-implantation genetic testing (PGT) can be classified as either pre-implantation genetic diagnosis (PGD) or pre-implantation genetic screening (PGS). PGS aims to improve the outcome of assisted reproductive technology (ART) treatment for the subfertile by testing for a number of the more frequent chromosome aneuploidies in an attempt to improve implantation and reduce the incidence of miscarriage. The first successful clinical application of PGD, to avoid the X-linked condition adrenoleukodystrophy, used polymerase chain reaction (PCR) to amplify a specific repeat on the Y chromosome in order to sex embryos. Patients performing embryo biopsy must be approved and licensed by the Human Fertilisation and Embryology Authority (HFEA) after inspection. The use of PGD for the prevention of transmission of serious genetic disease has largely been overtaken in volume by use of embryo biopsy to improve in vitro fertilisation (IVF) outcome for subfertile couples.