CONTROLLED OVARIAN STIMULATION FOR FREEZE-ALL CYCLES

In recent years, we have witnessed a sharp increase in the use of “freeze-all” cycles, in which all cohort of eggs/embryos is being frozen. The goal of this chapter is to describe the best available evidence for all components of controlled ovarian stimulation in freeze-all cycles. The overall evidence suggests that in freeze-all cycles, physicians should aim to achieve between 15 and 20 oocytes. Ovarian stimulation can be commenced during the luteal phase, if necessary, with comparable results. The GnRH-antagonist protocol with a GnRH-agonist trigger seems to be most suitable for freeze-all cycles. It has the benefit of almost completely eliminating the risk of OHSS while not affecting oocyte and embryo quality. The addition of low-dose hCG (dual trigger) has been suggested to improve oocyte and embryo quality, but further research in freeze-all cycles is required. Moderate-quality evidence indicates that in freeze-all cycles, a moderate delay of two to three days in ovulation triggering may result in the retrieval of a higher number of mature oocytes without impairing the pregnancy rate. Freeze-all appears to be a suitable approach in cases of late follicular progesterone elevation.