Background however, approximately 15% of women with PCOS are resistant to CC. Successful conception requires adequate endometrial receptivity, which can be assessed using ultrasonography and Doppler studies. This study aimed to evaluate the effect of a fixed‑dose extended letrozole regimen on endometrial receptivity-assessed by endometrial thickness, endometrial volume, and uterine artery Doppler indices in CC‑resistant PCOS patients.Materials & Methods: This prospective interventional study was conducted at the High Institute for Infertility Diagnosis and Assisted Reproductive Technologies, Al Nahrain University, Baghdad, Iraq, between March 2023 and March 2024. A total of 54 infertile women aged 20-40 years with a confirmed diagnosis of PCOS and documented CC resistance were enrolled. Endometrial thickness, endometrial volume, and uterine artery Doppler indices (Pulsatility Index PI and Resistive Index RI) were assessed after CC treatment and following an extended letrozole regimen (5 mg daily for 10 days).Results: Letrozole treatment was associated with a significant increase in endometrial thickness, endometrial volume, PI, and RI compared with CC treatment (P<0.05 for all). Endometrial thickness showed a significant inverse correlation with patient age after letrozole therapy (r= -0.38, P=0.005).Conclusion: Extended‑duration letrozole therapy significantly improves endometrial receptivity parameters in women with CC‑resistant PCOS and represents an effective option for ovulation induction following CC failure.
Mohammed et al. (2026) studied this question.