The Estrogen-primed Antagonist protocol is our favorite for patients with very low ovarian reserve, or those who have poor response after taking BCP.
In this protocol, the pretreatment cycle is a natural cycle (no BCP). About a week after ovulation, a GnRH antagonist (Ganirelix or Cetrotide) is started to prevent premature recruitment of follicles, an effect often seen in premature aging ovaries. In addition, estrogen is used to provide the young follicles an optimal condition to grow. Stimulation medications are stated on day 3 of the next menses and the antagonist would be used again later to prevent premature ovulation.
At IVFMD, we use the estrogen-primed Antagonist protocol for patients with very low egg reserve (AMH <0.5 ng/ml or total antral follicle count of 5 or less). It avoids the suppressive effect of Lupron and BCP on the ovaries. In addition, the use of estrogen during the pretreatment cycle prevents premature recruitment of follicles that can reduce the number of follicles available for stimulation.
Studies have shown that this protocol allows more gradual and coordinated growth of follicles resulting in improvement of embryo quality and quantity. The main disadvantage of this protocol is the lack of flexibility in planning the cycle since ovarian stimulation can occur on any day.