Preimplantationstester

Preimplantationstester is a term used in reproductive medicine to describe tools, methods, or entities designed to evaluate embryos before implantation during assisted reproductive technology. The term is not widely used as a fixed designation in English and is commonly associated with preimplantation genetic testing (PGT) and embryo viability assessment. The aim is to identify embryos with genetic abnormalities or to select those with the best chance of a healthy pregnancy.

Most widely used forms are preimplantation genetic testing for aneuploidy (PGT-A), testing for monogenic diseases (PGT-M), and testing for chromosomal structural rearrangements (PGT-SR). These tests analyze DNA from a few cells obtained through a blastocyst biopsy, typically on day 5 or 6 after fertilization. The genetic analysis uses methods such as PCR, microarray, or next generation sequencing to detect chromosomal copy number variations or specific disease-causing mutations. Embryos with normal results are more likely to implant successfully, though results are not infallible.

Typical workflow involves ovarian stimulation and egg retrieval, fertilization, culture to the blastocyst stage, biopsy of trophectoderm cells, genetic analysis, vitrification of affected or unaffected embryos, and eventual transfer of selected embryos in a subsequent cycle. Some centers also use non-genetic viability assessments, including time-lapse imaging and morphologic scoring, to supplement genetic information.

Limitations include mosaicism, which can lead to discordant results between biopsied cells and the entire embryo; potential risks from biopsy, though generally low; cost and accessibility; and uncertainty about the correlation between test results and live birth. Ethical and regulatory considerations vary by jurisdiction and can influence the availability and use of preimplantation testing.