Prevalence of ovarian hyperstimulation in normal responders receiving letrozole in assisted reproductive technology

Introduction
The use of letrozole, a selective aromatase inhibitor, induces follicular maturation. Randomized controlled trials addressing the utility of letrozole in normal responders are few. We evaluated whether incorporation of letrozole could be effective in decreasing ovarian hyperstimulation syndrome (OHSS) in normal responders undergoing intracytoplasmic sperm injection cycles.
Objective
The objective of this study was to compare the aromatase inhibitor (letrozole) with low-dose gonadotropins versus the standard long protocol for controlled OHSS in normal responder women undergoing intracytoplasmic sperm injection in terms of OHSS.
Patients and methods
This was a randomized noninferiority clinical trial registered in clinicaltrials.gov (NCT02429999). This study was conducted in Assiut University Fertility Center, from January 2015 to April 2016, and included 61 normal responder women randomized in a 1: 2 ratio. Twenty-one women (study group) received letrozole at a 10 mg daily dose from days 3 to 7 together with follicle-stimulating hormone (FSH) 75 IU/day from day 5. Gonadotropin-releasing hormone antagonist (orgalutran 0.25) is given when the follicle size is equal to 14 mm until human chorionic gonadotropin injection. Forty women (control group) received 0.1 mg decapeptyl from day 21 in the preceding cycle and continuously stimulated by FSH (150–225 IU/day) from day 2. The total dose of FSH received, number of mature oocytes, good-quality embryos, and OHSS were evaluated in both groups. Statistical analysis was done using Student's -test and -test when appropriate.
Results
Comparable rates for maturation index, fertilization, and good-quality embryos were yielded by both groups. The incidence of OHSS was significantly lower in the letrozole group compared with the long protocol group ( = 0.03).
Conclusion
Minimal stimulation protocol using letrozole with gonadotropins may form an effective tool to decrease the incidence of OHSS in in-vitro fertilization cycles in normal responding women.