Extended versus conventional letrozole regimen in patients with polycystic ovary syndrome undergoing their first ovulation induction cycle: a prospective randomized controlled trial

• Published in: Human reproduction open 2024-06, Vol.2024 (3), p.hoae046
• Main Authors: Zhu, Xiuxian, Lang, Jingwen, Wang, Qiaoling, Fu, Yonglun
• Format: Article
• Language: English
• Subjects: Drug therapy; Original; Stein-Leventhal syndrome
• ISSN: 2399-3529; 2399-3529
• DOI: 10.1093/hropen/hoae046

Abstract STUDY QUESTION Can an extended letrozole (LE) regimen result in a higher ovulatory rate than a conventional regimen in patients with polycystic ovary syndrome (PCOS) undergoing their first ovulation induction cycle? SUMMARY ANSWER There was no statistical difference in ovulation rate between patients with PCOS using the extended LE regimen and those using the conventional LE regimen. WHAT IS KNOWN ALREADY LE has become the first-line agent for ovulation induction. However, there is still a proportion of non-responsive cycles in patients with PCOS undergoing ovulation induction therapy with LE alone, and the extended LE regimen has been demonstrated to be a feasible method for inducing ovulation in these non-responders. Nevertheless, whether the extended regimen could be applied to all patients with PCOS as a first choice for the induction of ovulation remains to be explored. STUDY DESIGN, SIZE, DURATION This was a prospective randomized controlled trial that included 148 female patients with PCOS who underwent their first ovulation induction cycle with LE from January 2021 to October 2022. PARTICIPANTS/MATERIALS, SETTING, METHODS Participants were randomly assigned to receive an extended (5 mg LE daily for 7 days) or conventional regimen (5 mg LE daily for 5 days) for one treatment cycle. The ovulation rate was the primary outcome. Secondary outcomes included the clinical pregnancy rate, the number of preovulatory follicles, and the rate of multiple pregnancies. MAIN RESULTS AND THE ROLE OF CHANCE The ovulation rate among patients receiving an extended LE regimen was slightly higher than the rate with a conventional LE regimen, but the difference did not reach statistical significance in either the intention-to-treat analysis (90.54% [67/74] vs 79.73% [59/74], P = 0.065; relative risk [95% CI]: 0.881 [0.768–1.009]) or the per-protocol analysis (90.54% [67/74] vs 84.29% [59/70], P = 0.257; relative risk [95% CI]: 0.931 [0.821–1.055]). The number of preovulatory follicles was nearly identical in the two groups (1.39 ± 0.62 vs 1.37 ± 0.59, P = 0.956), and no cases of ovarian hyperstimulation syndrome were observed. With regards to the endometrial parameters, the mean endometrium thickness was slightly thicker with the conventional LE regimen compared to that with the extended LE regimen, though with no statistical difference (9.27 ± 1.72 mm vs 9.57 ± 2.28 mm, P = 0.792). In the per-protocol analysis, the rates of clinical pregnancy (20.27% [15/74] vs