Traditionally, studies about In Vitro Fertilization (IVF) examine and report the 'per cycle' and 'per embryo transfer procedure' probability of pregnancy and delivery .Thus, each IVF cycle is considered as a unique entity even if several embryo transfers (ET) have been performed after a single ovarian stimulation.~Thanks to the latest technological refinements, in recent years the number of thawed frozen ETs has greatly increased and has become an essential feature of IVF procedures .This practice has been encouraged by the strategy of preferring single ET for reducing multiple pregnancy and preventing ovarian hyperstimulation in high risk women.~Moreover, at first infertility counseling patients usually want to know which is their possibility to have a live birth child with ART treatment, after the first stimulation cycle, also involving the chances after frozen ET or frozen oocytes injection.~Live birth rate (LBR) after a single fresh or frozen ET appears, at present time, to be an insufficient parameter for a realistic evaluation of the efficacy of an IVF program.~We need to identify a new parameter for the evaluation of the success rate of IVF techniques which should incorporate outcomes associated with a single controlled ovarian stimulation cycle. Specifically, Cumulative live birth rate (CLBR) has been suggested as a suitable way for reporting success of IVF program : it implies capturing the totality of live birth episodes following successive treatments.~For patients CLBR is very reliable and easy to understand because it summarizes the chance of a live birth over an entire treatment period . CLBR per oocyte retrieval is more meaningful as it is the best indicator of quality and success in IVF and it allows the best indicator of quality and success in IVF with different strategies for freezing embryos.~The aim of the present study was to report our experience on CLBR after the first stimulation cycle and to determinate which prognostic factors contribute to positive pregnancy outcomes.
We need to identify a new parameter to evaluate the success rate of IVF techniques. CLBR has been suggested as a suitable way for reporting success of IVF program: it implies capturing the totality of live birth episodes following successive treatments. For patients CLBR is easy to understand because it summarizes the chance of a live birth over an entire treatment period. CLBR per oocyte retrieval is more meaningful as it is the best indicator of quality and success in IVF and it allows the best indicator of quality and success in IVF with different strategies for freezing embryos.