Fertilization Rate
The percentage of mature oocytes that successfully fertilize after insemination or ICSI, typically reported 16-20 hours post-procedure.
Full Definition
Fertilization rate is a key laboratory outcome measure calculated as the number of normally fertilized oocytes (showing two pronuclei) divided by the number of mature oocytes inseminated, expressed as a percentage. Normal fertilization rates typically range from 60-80% for conventional IVF and 70-85% for ICSI. This metric helps evaluate sperm quality, oocyte competence, and laboratory performance. In clinical reports, fertilization rates are documented alongside other cycle parameters and influence decisions about fresh versus frozen embryo transfer.
Usage
Usage note: Always specify whether the rate refers to conventional IVF or ICSI, as success rates differ between methods.
In Context
- "The cycle achieved a fertilization rate of 75% with 6 of 8 mature oocytes fertilizing normally." — Laboratory report
- "Low fertilization rates in previous cycles indicated the need for ICSI in this treatment." — Treatment protocol