ABSTRACT
In a spontaneous menstrual cycle, only one follicle out of a cohort of 10–20 usually completes maturation and ovulates to release a mature oocyte. The aim of controlled ovarian stimulation (COS) in assisted reproductive technology (ART) protocols is to overcome the selection of a dominant follicle and to allow the growth of a cohort of follicles. This strategy leads to an increase in the number of oocytes and hence embryos available for transfer, thereby increasing the chance of transferring viable embryos. However, the chance of pregnancy and also live birth begins to dramatically decline after the age of 35 years, and successful treatment for these patients continues to be a major challenge in ART programs.
