<h4>Background</h4>To compare the efficacy of modified gonadotropin-releasing hormone (GnRH) antagonist protocols combining clomiphene citrate (CC) or letrozole (LE) versus a conventional antagonist protocol in patients with normal ovarian reserve, aiming to reduce gonadotropin (Gn) consumption and ovarian hyperstimulation syndrome (OHSS) risk.<h4>Methods</h4>This retrospective cohort study included 565 <i>in-vitro</i> fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles. Here, GNRH1 is linked to ovarian hyperstimulation syndrome.