Impact of Letrozole on Prevention of Early Onset Ovarian Hyperstimulation Syndrome in GnRH Antagonist Protocol: A Randomized Controlled Trial

Abstract Background Ovarian hyperstimulation syndrome (OHSS) is a risk associated with assisted reproductive technology. There is a link between higher incidences of OHSS and higher blood estrogen levels. With its strong, targeted, and reversible inhibition of aromatase and E synthetase, the nonsteroidal aromatase inhibitor letrozole can prevent the conversion of androgens into estrogens. Methods Study populations were divided into two equal groups: Group I: Consisted of 85 women who received controlled ovarian stimulation with a conventional antagonist protocol and letrozole. Group II: Consisted of 85 women who received controlled ovarian stimulation with a conventional GnRH antagonist protocol and a placebo. Results There were statistically significant differences among the groups in terms of Estradiol level on Trigger Day (p = 0.037), Number of oocytes retrieved (p = 0.018). The total days of stimulation and cumulative Gonadotropin dose were significantly lower in the Letrozole group (p = 0.045). There were no significant differences between the groups as regard endometrial thickness at trigger day, number of fertilized oocytes, fertilization rate, embryos transferred per cycle, and fresh embryos transferred, mild and critical early onset OHSS, Cycle cancels, Biochemical pregnancy, and Clinical pregnancy between the two groups (P > 0.05). There was a significant difference as regard moderate and severe early onset OHSS between the two groups (P < 0.05). Conclusion We've concluded that for PCOS patients facing a high risk of OHSS, supplementing the GnRH-ant protocol with LE offers a safer, more effective, cost-efficient, and patient-friendly approach compared to the traditional GnRH-ant protocol. The use of LE alongside conventional protocols might alleviate severe forms of OHSS, even among those at extreme risk, without compromising the potential for implantation, pregnancy, and delivery