Step 1: Control ovarian hyperstimulation
Control ovarian hyperstimulation is done using different protocols. The most common one is an GnRH antagonist protocol where the secretion of gonadotropin hormones is suppressed in order to prevent premature ovulation. Once optimal suppression is achieved, the next step is the recruitment of multiple follicles by daily injections of gonadotropins. Ultrasound imaging and hormone assessments are used to monitor follicular development. When the lead follicles have reached the appropriate size, the final maturation of eggs is completed by HCG administration. Egg retrieval is scheduled 34-36 hours after HCG injection.