Improvements in ovarian stimulation for in vitro fertilization

What are the major improvements in stimulation over recent years? The stimulated cycle has completely superseded the natural cycle since this is the only method of obtaining several embryos. In conventional stimulation, despite an enormous body of literature, no single treatment modality has emerged as superior to other forms of therapy. Undoubtedly it is the experience and habits of individual IVF teams that determine the success of one or another method. Therefore programmed stimulation is an improvement in that it introduces the factors of convenience and simplicity while retaining the clinical efficacy of stimulation by conventional treatment. The analogues of LHRH are still in an early phase of development, but they appear to be associated with a low cancellation rate even in previous poor-responders. Furthermore, preliminary results seem to indicate that this is the first development since the widespread adoption of follicular stimulation, which is associated with an increased pregnancy rate. We are currently involved in trying to associate programmed stimulation and analogue treatment in a bid to combine the advantages of both therapies. Finally, embryo cryopreservation must be mentioned. There is no point in refining our stimulation protocols to obtain many embryos if those surplus to immediate requirement are disposed of. Cryopreservation offers the means of maximizing the pregnancy potential of a single IVF cycle while reducing the possibility of multiple pregnancy.