Comparative effectiveness of sildenafil citrate and estradiol valerate as adjuvants during clomiphene citrate-assisted ovarian stimulation cycles in patients with unexplained infertility: a double-blind randomized controlled trial.

Objective: This study aimed to assess the effect of sildenafil citrate and estradiol valerate as adjuvant therapy during ovarian stimulation cycles with clomiphene citrate in patients with unexplained infertility in Kisangani.

Method: A double-blind, randomized controlled trial was conducted for two years at two specialized health facilities in Kisangani (University Clinics of Kisangani and "Clinique des Anges Kisangani"). The population included 148 patients, 74 of whom were on clomiphene citrate + sildenafil citrate (CCSC) regimens and 74 of whom were on clomiphene citrate + estradiol valerate (CCEV) regimens for three months. The primary indicator was the conception rate, with secondary outcomes encompassing endometrial thickness, appearance and vascularity, the number of mature follicles and ovulation rate.

Results: The two groups were comparable in terms of sociodemographic and clinical characteristics. The mean duration of attempting to conceive was 4.39 years versus 4.36 years (P = 0.839), while the mean AFC was 11.51 versus 11.46 (P = 0.831), in the CCSC group versus CCEV group respectively. Secondary infertility was the most frequent diagnosis in each of the two groups. The biochemical pregnancy rate was comparable between the two groups (P = 0.385), while the clinical pregnancy rate was significantly higher in the CCSC group versus CCEV group (P = 0.04). Both perifollicular flow and the ovulation rate were significantly higher in the CCSC group versus the CCEV group (P = 0.006 and P = 0.002 respectively). However, endometrial vascularity/thickness, and the number of Graafian follicles were not significantly different between the two groups.

Conclusion: As an adjuvant, sildenafil increases the rate of clinical pregnancy more than does estradiol in patients with unexplained infertility undergoing ovarian stimulation with clomiphene citrate.

Study registration: PACTR 202,310,849,449,401 (Pan African Clinical Trials Registry).