The Effect of Bazedoxifene and Fulvestrant for Preventing Ovarian Hyperstimulation Syndrome: An Experimental Study

<b>Background:</b> Ovarian hyperstimulation syndrome (OHSS) remains a major complication during controlled ovarian stimulation, particularly in women with high estradiol levels. This study aimed to investigate whether bazedoxifene or fulvestrant could be effective in preventing OHSS. <b>Methods:</b> Forty 22-day-old Wistar albino rats were randomly assigned to four groups (<i>n</i> = 10 each). Group 1 received saline (negative control). Group 2 received pregnant mare serum gonadotropin (PMSG) plus hCG (positive control). Group 3 received PMSG + hCG plus fulvestrant, and Group 4 received PMSG + hCG plus bazedoxifene. Rat weight, peritoneal fluid, follicle counts, serum estradiol and VEGF levels, and ovarian ER/VEGF immunoreactivity were evaluated. <b>Results:</b> Peritoneal fluid was absent in controls but detected in 80% of positive controls and 40% of both treatment groups. Tertiary follicles and atresia were significantly higher in OHSS rats compared to controls. Fulvestrant reduced stromal ER expression, while bazedoxifene increased it. Both drugs decreased ascites formation and weight gain. Fulvestrant treatment showed unexpectedly elevated serum estradiol levels, likely due to assay interference. <b>Conclusions:</b> Fulvestrant and bazedoxifene may reduce OHSS severity by lowering ascites formation and weight gain. These agents could be potential therapeutic candidates for OHSS with appropriate timing and dosage.