This study wants to comparing letrozole plus misoprostol with misoprostol alone in termination of nonviable pregnancy in the first trimester . Study Design : Randomized , Single-blind , Two- center , Controlled with standard treatment without placebo. Target population: Pregnant women with under 12 weeks nonviable pregnancy. Inclusion criteria : pregnancy with under 12 weeks nonviable fetus without any other systemic or emergency problems . Main exclusion criteria : any condition requiring emergency intervention . Sample size: 124 participants were randomized into two groups. In this study , control group use Misoprostol for abortion (gold standard treatment) and intervention group will receive Letrozole plus Misoprostol . in Intervention group, 3 days after treatment will check the serum level of Estradiol then both groups will receive Misoprostol tablets 600 mg orally as a single dose. Patients will be monitored for 4 hours after taking Misoprostol to the complications like bleeding and abdominal pain , then will discharge. The next visit will take about 15 days later and Ultrasonography for رRetained Products of Conception and check the hemoglobin level. If abortion not happen,then curettage will take place. Patients based on the evaluation results (abortion happen or not) will be divided in two groups (response and non-response) to treatment. Primary out come is rate of complete abortion and Secondary outcomes are rate and duration of bleeding and other side effects such as nausea , vomiting , diarrhea , dizziness , headache , pain in the lower part of the abdomen , fever and chills and differences in serum level of estradiol before and after treatment with Letrozole .