A Prospective Randomised Comparative Clinical Trial Study of Luteal PhaseLetrozole versus Ganirelix Acetate Administration to Prevent Severity of Early Onset OHSS in ARTs

Ovarian hyperstimulation syndrome (OHSS) is the most notable complication in ovulation induction for assisted reproductive techniques (ARTs) like in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). Hence, we decided to evaluate the effect of the aromatase inhibitor, letrozole, versus gonadotrophin-releasing hormone (GnRH)-antagonist (ganirelix acetate) on prevention of severity of OHSS and reduction in serum estradiol (E2) levels when administered during the luteal phase after oocyte retrieval in IVF/ICSI cycles. In this prospective single-centred, randomized, parallel-arm study, 122 patients were randomized to receive oral letrozole (n=61, 2.5 mg twice daily) or ganirelix acetate (n=61, 0.25 mg subcutaneously daily) from the day of egg retrieval for the next 7 days. Incidence and severity of early OHSS were the primary endpoints assessed by the signs, symptoms, and laboratory findings of OHSS (e.g., serum E2 levels). The secondary endpoints were patient satisfaction and the additional cost of therapy to prevent the severity of OHSS. Letrozole group had lower incidence of OHSS (13.1%) compared to 19.6% in ganirelix acetate group (P=0.32). Serum E2 levels on post-pick up days 5 and 7 were significantly lower in the letrozole group when compared to the ganirelix acetate group (P=0.001). The majority of the patients in both groups had no major complications. No significant difference was found between the study groups with respect to the incidence of OHSS (P=0.33). The additional cost per IVF cycle for prevention of severity of early-onset OHSS in the letrozole group was 5.32 USD compared to 267.26 USD in the ganirelix acetate group, which was almost fifty times costlier. Letrozole and ganirelix acetate have the same efficiency for the overall prevention of OHSS, whereas letrozole was more effective in preventing moderate OHSS. Letrozole had better patient satisfaction and is cheaper compared to GnRH antagonists (Registration number: CTRI/2020/10/028674).