There are two main stimulation protocols for the patients considering IVF : Short antagonist protocol using GnRH antagonist medication and long agonist down regulation protocol also known as Luteal Lupron protocol. Stimulation protocol that is assigned to the patient by the IVF specialist depends on the age, hormonal levels, previous failed stimulation protocols and many other factors.

Short antagonist protocol is when stimulation is started on day second or third of menses with the injections containing FSH ( Follicle Stimulation Hormones). Most frequently used FSH injections are Gonal f and Menopur. On around day 6 of stimulation Cetrotide is added. After close monitoring of follicle sizes on the ultrasound scan, when follicles are considered to be mature and ready for retrieval, HCG (Human chorionic gonadotropin) injection is given 34-36 hours before retrieval is performed. FSH injections and Cetrotide are not injected after HCG. Stimulation with short protocol may last between ten to fifteen days. Short antagonist protocols are most commonly used recently as it has significant advantages: it is shortening the stimulation time and reduces the amount of stimulation injections that are used. Consequently the total cost of the procedure is quite low.

Long agonist protocol is commonly used in many countries, including USA. With this protocol Lupron is started 7 days before the next expected period known as mid luteal timing. FSH injections are started between three to seven days after the menses start. Egg retrieval is performed 10-12 days after starting FSH injections. HCG trigger is given 34-36 hours before. It is needed to induce final egg maturation. HCG is given when estradiol level and follicle sizes look best to get successful results of IVF. Being extended in time and requiring higher amounts of injections may be considered as slight disadvantage of long agonist down regulation protocol.

Stimulation method and doses are adjusted by the IVF doctors depending on many factors. Prior to starting the stimulation, follicle count is done along with all hormonal screening including AMH (Anti Mullerian Hormone), LH (Luteinizing hormone) and FSH ( Follicle Stimulating Hormone). Patients with high number of follicles and high AMH level are starting the stimulation with lower doses of FSH injections. This reduces the risk of overstimulation of the ovaries. Based on gradual checkups during the stimulation, measuring follicle sizes and Estrogen level, doses are either maintained the same or increase/decrease is advised.