The cumulative rate measures the probability of an outcome (like pregnancy or live birth) after a series of embryo transfers or IVF cycles. It usually assumes that all embryos created from these cycles are transferred, although some may be left over depending on the specific study.
For instance, if the cumulative live birth rate is 50% after five IVF cycles, it means that there is a 50% chance of achieving a live birth after completing five cycles and transferring all available embryos.
Cumulative rates are not always linked to the number of cycles. They can also be based on the number of transfers. For example, a cumulative live birth rate of 98.1% for transferring five euploid embryos means that transferring five euploid embryos sequentially results in a 98.1% chance of a live birth.