Clinical Outcomes Of Sildenafil Application In Patients Of Poor Endometrial Development

Background Poor endometrial development(PED)is a general description of endometrial thickness and morphology,with abnormalities in endometrial and morphology usually indicating poor endometrial receptivity(ER).Nitric oxide(NO)can activate guanylate cyclase(GC)to promote the conversion of guanosine triphosphate(GTP)to cyclic guanosine monophosphate(cGMP),which can eventually relax smooth muscle by inhibiting Calcium(Ca2+)effects,thus leading to increased blood perfusion.cGMP can also be degraded by phosphodiesterase(PDE)to reduce this effect,and sildenafil citrate(SC)can inhibit the activity of PDE to prevent the degradation of cGMP.Thus,SC can promote the increase of blood flow induced by cGMP.Theoretically,we believe that SC may increase endometrial blood perfusion through the above approaches,thereby promoting the increase of endometrium thickness(EM),which is further expected to improve the clinical pregnancy outcome in patients of poor endometrial development.Objective The purpose of this study was to investigate the effect of SC on endometrium and pregnancy outcome of patients with poor endometrial development(PED)during frozen embryo transplantation.Materials and methods This study included 472 infertility patients who underwent in vitro fertilization/intracytoplasmatic sperm injection and frozen-thawed embryo transfer(IVF/ICSI-FET)and suffered from poor endometrial development in the hormone replacement cycle(HRC)from April 2017 to July 2019.The patients were divided into two groups:the sildenafil group(n=88)and the control group(n=384).Endometrial thicknesses and types on endometrial transformation day,as well as pregnancy outcomes after FET(biochemical pregnancy,clinical pregnancy,early abortion,late abortion,and live birth rates)between two groups were analyzed.Then According to endometrial thickness after 10 days of estradiol valerate treatment,they were further divided into 3 subgroups(8>EM≥7mm,7>EM≥6mm,6mm>EM).Outcomes the sildenafil and control group were not statistically different of the thickness of EM after 10 days of estradiol valerate application(P=0.003).While the endometrial type after 10 days of estradiol valerate application have no statistical significance(P>0.05).The thickness of EM on endometrial transformation day was thinner in the SC than that of the control group(P=0.035).No differences were observed in the endometrial type on endometrial transformation day and the growth of EM between the two groups(P>0.05).In the further subgroup analysis,after excluding the influence of confounding factors,the three subgroups all showed similar results.the application of SC was not associated with either the thickness and the type of EM on the day of endometrial transformation or the growth of EM.Conclusions During the endometrial preparation of hormone replacement for IVF/ICSI frozen embryo transplantation,SC could not better endometrial development and pregnancy outcomes in patients with poor endometrial development.