Preimplantation Genetic Diagnosis and Screening (PGD/PGS) for monogenic diseases and/or numerical/structural chromosomal abnormalities is a tool for embryo testing aimed at identifying nonaffected and/or euploid embryos in a cohort produced during an IVF cycle. A critical aspect of this technology is the potential detrimental effect that the biopsy itself can have upon the embryo. Different embryo biopsy strategies have been proposed. Cleavage stage blastomere biopsy still represents the most commonly used method in Europe nowadays, although this approach has been shown to have a negative impact on embryo viability and implantation potential. Polar body biopsy has been proposed as an alternative to embryo biopsy especially for aneuploidy testing. However, to date no sufficiently powered study has clarified the impact of this procedure on embryo reproductive competence. Blastocyst stage biopsy represents nowadays the safest approach not to impact embryo implantation potential. For this reason, as well as for the evidences of a higher consistency of the molecular analysis when performed on trophectoderm cells, blastocyst biopsy implementation is gradually increasing worldwide. The aim of this review is to present the evidences published to date on the impact of the biopsy at different stages of preimplantation development upon human embryos reproductive potential.

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The Impact of Biopsy on Human Embryo Developmental Potential during Preimplantation Genetic Diagnosis.

Amniocentesis and chorionic villus sampling have been shown through prospective, multicenter trials to be safe and effective methods of prenatal diagnosis; accordingly, a knowledge of these tests is important for those physicians who care for women during their childbearing years. We review the indications, techniques, safety, accuracy, and efficacy of amniocentesis and chorionic villus sampling and compare the advantages and disadvantages of each diagnostic test. This review should enable physicians to provide appropriate counseling and information to women at increased risk for fetal abnormalities detectable by either of these procedures.

Amniocentesis and chorionic villus sampling.

It has become accepted medical practice to inform pregnant women 35 years of age and older of their increased risk of having a child with chromosome abnormality in comparison to younger women, and ...

Genetic counseling for the older pregnant woman: new data and questions.

The work of one Genetic Centre over 16 years, covering about 14 000 kinships, is described. The numbers registered in a year increased from an average of 477 in the early 1960s to 1612 in 1976/1977. The increase is largely, but not entirely, attributable to the advent of prenatal diagnosis, and an account is given of our experience with this. In 1916 patients who had a successful amniocentesis, results indicative of fetal abnormality were found in 4.3% and a balanced translocation was found in an additional 0.9%. Results indicative of fetal abnormality were found in 3.5% of mothers referred because of a maternal age of 40 or more, 3.9% referred because of a high risk of neural tube defect, and 19.3% referred because of a high risk of an inborn error of metabolism. A number of cases with difficult diagnostic problems are described.

Sixteen years' experience ofcounselling, diagnosis, andprenatal detection inone Genetic Centre: progress,results, andproblems

Chorionic villus sampling has gained importance as a tool for early cytogenetic diagnosis with a shift toward first trimester screening. First...

W A Miller

Papers

Prenatal diagnosis of genetic disorders.