Objectives: Miscarriage is a common pregnancy complication causing substantial psychiatric complications. This study was designed to investigate whether the administration of brief supportive psychotherapy (BSP) is effective on the management of women with miscarriage when conducted in the first 24 hours of hospitalization in order to prevent symptoms of anxiety, depression, and grief at four-months post-miscarriage. Methods: We conducted a randomized clinical trial on 79 women with miscarriage hospitalized in Ayatollah Rohani teaching hospital. The women were randomly assigned into two groups (39 in the experimental group and 40 in the control group). All interventions were implemented for two study groups during the first 24 hours of hospitalization in a private room in the hospital. The experimental group received a two-hour BSP. The objective outcomes were assessed using Hospital Anxiety and Depression Scale and Perinatal Grief Scale (PGS), which has three subscales (active grief, difficulty coping, and despair) and were measured before the intervention and at four-months post-miscarriage. Results: The results of pre tests in the follow-up of the trial suggested that the participants who received BSP reported significant reductions in the mean scores of active grief (-34.2±9.7 vs. 28.1±-6.9), difficulty coping (27.1±6.4 vs. 23.3±4.3), despair (28.0±8.4 vs. 22.8±5.2), and total PGS (89.6±23.1 vs. 74.4±15.3), in contrast to participants in the control group who did not report such results. Further, the results of generalized estimating equations models revealed that brief supportive psychotherapy caused a significant decrease in the level of factors including active grief, difficulty coping, despair, total perinatal grief, anxiety symptoms, and depressive symptoms in subjects in the experimental group compared to those in the control group after miscarriage. Also, the frequency of anxiety symptoms (13.5% vs. 60.5%), depressive symptoms (32.4% vs. 71.1%), and grief symptoms (10.8% vs. 65.8%) was found to be significantly lower in the group receiving psychotherapy than in the control group at four-months follow-up. Conclusions: Administration of BSP session during the first 24 hours of hospitalization for women with miscarriage can be considered a reliable method to prevent anxiety symptoms, depression symptoms, and perinatal grief at four-months follow-up.