A pilot study to prevent a thin endometrium in patients undergoing clomiphene citrate treatment

ABSTRACTS: BACKGROUND: Clomiphene citrate (CC) is most commonly used as a first-line treatment of infertility. However, a disturbance of endometrial growth by the adverse effects of the CC has been recognized. Since a thin endometrium is recognized as a critical factor of implantation failure, preventing CC-induced thinning of the endometrium is important. This study was undertaken to investigate whether the modified CC treatments are useful to prevent a thin endometrium in patients undergoing CC treatments. METHODS: This study is a prospective, randomized controlled study. The study was performed at the Saiseikai Shimonoseki General Hospital during a 4-month period (May 2012 to September 2012). Sixty-six infertile women who had a thin endometrium (< 8 mm) during the standard CC treatment (50 mg/day on days 5–9 of the menstrual cycle) were enrolled. The patients were randomly divided into three groups: 22 patients were given 25 mg/day CC on days 5–9 (half-dose group), 22 patients were given 50 mg/day CC on days 1–5 (early administration group) and 22 patients received a standard CC treatment again (control group). Endometrial thickness at the induction of ovulation was assessed by ultrasonography. The primary endpoint of this study was an endometrial thickness. RESULTS: Half dose administration and early administration improved the endometrial thickness (≥ 8 mm) in 14 patients (70%) and in 19 patients (90%) respectively, while only 3 patients (15%) improved in endometrial thickness in the control group. The mean endometrial thickness was also significantly higher in the half dose group (8.6 ± 1.5 mm) and early administration group (9.4 ± 1.5 mm) compared to the control group (6.7 ± 1.8 mm). No side effect was observed in this study. CONCLUSIONS: The modified treatment with a half-dose or early administration of CC significantly increased endometrial thickness in patients with a history of thin endometrium caused by the standard CC regimen. The modified CC treatments in this study can be beneficial for patients with a thin endometrium as a result of standard CC treatment. TRIAL REGISTRATION: Clinical Trial Registration Number: UMIN000007959.