Aim: The purpose of this study is to determine whether a low dose of Sildenafil citrate during the first trimester of pregnancy helps pregnant women who have experienced repeated miscarriages without a clear cause. Patients and methods: There were two groups of pregnant women in this randomized controlled experiment; one group had a history of many, unexplained miscarriages in the first trimester, while the other group did not, each group consisting of 50 pregnant patients: Group I: 50 participants received aspirin 75 mg/ day oral tablet & folic acid 5 mg/ day oral tablet. 2) Group II: 50 participants received aspirin 75 mg/ day oral tablet, folic acid 5 mg/ day oral tablet, and sildenafil citrate 20 mg tablets once daily. The treatment will continue till 14 weeks of gestation. All patients were subjected to a complete history and clinical examination. Ultrasound examination was done for confirmation of pregnancy, dating in early pregnancy, and cervical dimension was done for exclusion of cervical incompetence. Results: Our study showed that there was a significantly lower PI and RI between the sildenafil group than the control groups in the 10th week (p-value <0.05). There was a significantly higher rate of completeness of pregnancy in the sildenafil group than in control groups till the 14th week of gestation (P-value <0.05). Conclusion: Oral sildenafil citrate in low dose 20mg increases uterine artery blood flow, which is reflected by PI and RI. Oral sildenafil citrate in a low dose of 20mg with Folic acid 5mg and Aspirin 75mg reduces the incidence of occurrence of unexplained recurrent miscarriage during 1st trimester of pregnancy.