Clinical outcomes of three- or five-day treatment with clomiphene citrate combined with gonadotropins and a timed intercourse cycle in polycystic ovary syndrome patients

Objective: This study aimed to investigate the effect of a new clomiphene citrate (CC) regimen on preventing thin endometrial lining in polycystic ovary syndrome (PCOS) patients receiving CC plus gonadotropin treatment with a timed intercourse cycle. Methods: A total of 114 women with PCOS were included in this trial. Patients were divided into two groups and treated in accordance with the controlled ovarian stimulation (COS) protocol. In group A, 104 COS cycles in 67 patients were included, and in each cycle 150 mg CC was given for three days, starting from day 3. In group B, 69 COS cycles in 47 patients were included, in which 100 mg CC was given for five days, starting from day 3. The thickness of the endometrium was measured on the day of human chorionic gonadotropin (hCG) injection. Timed intercourse was recommended at 24 and 48 hours after the hCG injection. Results: Additional doses of human menopausal gonadotropin and the number of days of hCG administration were not significantly different between the two groups. Endometrial thickness on the day of hCG administration was significantly larger in group A than group B (4$9.4{\pm}2.1mm$ vs. $8.5{\pm}1.7mm$, p=0.004). The pregnancy rate was significantly higher in group A than in group B (38.4% vs. 21.7%, p=0.030). Conclusion: Three-day CC treatment resulted in a significantly higher pregnancy rate than the standard five-day CC treatment in a timed intercourse cycle in PCOS patients. Facilitating adequate endometrial growth via the early discontinuation of CC might be a crucial factor in achieving a higher pregnancy rate.