| Abstract: | Successful embryo implantation depends on a well-functioning endometrium and high-grade quality embryos. An increasing body of evidence suggests that sildenafil citrate plays an important role in endometrial receptivity and implantation. However, few studies have investigated the effects of oral sildenafil citrate on the clinical outcomes of patients with recurrent implantation failure (RIF). In the present study, we aimed to determine the impact of sildenafil citrate on improving the endometrial blood flow and pregnancy rate in RIF patients. A total of 346 frozen-thawed transfer cycles from 305 RIF patients undergoing IVF at the Center for Reproductive Medicine of Peking University Third Hospital from June 2013 to December 2017 were enrolled. Oral sildenafil citrate was given to the patients, and the related effects on endometrial blood flow, endometrial thickness, and clinical outcomes were investigated. In the 346 transferred cases, the proportion of three groups (A: undetectable blood flow; B: sub-endometrial blood flow; C: endometrial and sub-endometrial blood flow) before and after oral administration of sildenafil citrate was as follows: group A: 36.7% ( n = 127) vs. 7.5% ( n = 26); group B: 42.8% ( n = 148) vs. 24.0% ( n = 83); group C: 20.5% ( n = 71) vs. 68.5% ( n = 237). Moreover, the endometrial blood flow in 137 FET cycles was improved (61.8%). Besides, the implantation rate was 19.47% (132/678), and the clinical pregnancy rate reached 32.66% (113/346), while the endometrial blood flow of the pregnancy group was better compared with the non-pregnancy group. This study explored the improving effects of sildenafil citrate on the endometrial receptivity and clinical outcomes of RIF patients, confirming the crucial role of good endometrial blood flow in a successful pregnancy. Meanwhile, the low incidence of adverse events also supported the security and feasibility of sildenafil citrate in the clinical therapy of RIF patients. |
