IVF BIG DATA PROJECT
Factors that define success of PGT
PGT outcomes are influenced by biology, lab processes, and clinical decisions. Below is a short, practical overview of the biggest drivers—starting with maternal age and the number of eggs retrieved.
We assembled the latest available data from 5,016 IVF PGT cycles in 2024–2025 (a total of 27,841 biopsied embryos). We know that everyone is different, but biology and science can at least give us some understanding of what we can expect and hope for.
The major factors at play are: maternal age and number of eggs retrieved. Maternal age is the most important factor that defines the euploidy rate (percentage of embryos that are free of major chromosomal abnormalities).
Euploidy rate, %
Euploidy rate is only part of the story. The expected number of euploid embryos per cycle also depends on how many embryos reach biopsy—so both quantity (embryos available for biopsy) and quality (euploidy rate) matter together. For example, if you have 10 embryos available for biopsy and the euploidy rate is 50%, you can expect 5 euploid embryos. Unfortunately, in the real world both euploidy rate and number of embryos available for biopsy are declining with maternal age. So, overall expected number of euploid embryos per cycle is also declining with maternal age.
Average embryos for biopsy and normal (euploid) embryos per IVF cycle
The silver lining is that when the euploid embryo was found the ongoing pregnancy rate is essentially is age-independent. So, 40 y.o. woman who gets 1 euploid embryo has the similar chance of pregnancy as 20 y.o. woman who gets 1 euploid embryo. this is where PGT shines the most - it eliminates the need for multiple IVF cycles where genetic status of embryos is unknown.
Maternal age (most important)
Maternal age strongly shapes the expected euploidy rate. As age increases, the probability that embryos are chromosomally normal generally decreases.
Number of eggs retrieved
More eggs generally increases the chance of producing at least one euploid embryo, but outcomes vary widely between patients and cycles.
Fertilization and blastulation
PGT outcomes depend on how many eggs fertilize and develop to the blastocyst stage. Lab conditions and embryo development biology both matter.
Biopsy & testing pipeline
Biopsy strategy, sample quality, and the testing workflow can affect result rates (e.g., no result, mosaic calls).
Try the tools
Use the prediction calculators to translate age and cohort data into expected counts and probabilities.