Results of in vitro fertilization with embryo cryopreservation and a recommendation for uniform reporting.

The analyzed data from 295 cycles in which certain embryos were frozen demonstrate a comparable aptitude for development of embryos either fresh or frozen-thawed in cycles yielding four or more embryos. This supports the clinical advantage of freezing certain embryos in this situation. However, there was no advantage in freezing embryos if only one to three were available in the IVF cycle. A formula is proposed to give the current outcome and to compare the success rate of IVF-ET according to various parameters, including the policy for embryo cryopreservation. This formula enables all teams to present their data in an identical manner.