GNRH1 and polycystic ovary syndrome: However, some studies suggested no significant difference in the fertilization rate, clinical pregnancy rate (CPR), and sustained pregnancy rate in the GnRH-ant pretreatment group.[16] In 2020, Maryam et al[17] conducted a prospective study to evaluate the effect of GnRH-ant pretreatment on pregnancy outcomes in patients with PCOS treated with an antagonist protocol during the early follicular phase.