Entering the field of assisted reproductive technology requires fluency in specialized terminology. This quick-reference A–Z glossary clarifies core clinical concepts.
Aneuploidy
A condition where an embryo has an abnormal number of chromosomes (e.g., Trisomy 21). PGT-A tests for aneuploidy prior to transfer.
Blastocyst
An embryo at Day 5 or 6 comprising an Inner Cell Mass (which forms the fetus) and an outer Trophectoderm layer (which forms the placenta), surrounding a fluid-filled blastocoel cavity.
CASA (Computer-Assisted Semen Analysis)
High-resolution digital optical microscopy combined with image tracking software to measure sperm motility velocities (VCL, VSL, VAP) and concentrations objectively.
Denudation
The enzymatic and mechanical stripping of outer cumulus oophorus and corona radiata cells from retrieved oocytes using hyaluronidase and calibrated micropipettes.
Intra-Cytoplasmic Sperm Injection (ICSI)
The micro-injection of a single immobilized spermatozoon directly into the cytoplasm of a mature M-II oocyte under 400x magnification.
Pronuclei (PN)
Nuclear structures visible 16–18 hours post-insemination. The presence of two distinct pronuclei (2PN) and two polar bodies indicates normal biparental fertilization.