Design: prospective clinical controlled study. Setting: high-risk pregnancy unit- Benha university hospital. Methods: Pregnant women with unexplained recurrent miscarriage attending high-risk pregnancy unit. 200 selected patients with previous unexplained recurrent miscarriage are divided into 2 groups: group A (n = 100) receive low-dose aspirin (81 mg once daily orally) plus heparin (5000 IU) every 12 h with the ﬁrst positive pregnancy test while group B (n = 100) receive no thing .