Background: The role of anticoagulant medications in preventing placental mediated pregnancy complications in patients with and without thrombophilia has not been investigated well. One underlying cause is associated with adverse effects of anticoagulants in pregnancy including teratogenicity, complexities in dosing and management of anticoagulants during pregnancy and labor. We aimed to assess effects of prophylactic anticoagulant medications in pregnant women with history of the PMPCs who were tested for hereditary thrombophilia.
Methods: This retrospective cohort study was done in obstetric clinics of Tehran University of Medical Sciences on medical records of 148 pregnant women with history of poor obstetric outcome due to placental complications. Pregnant women with both positive and negative thrombophilia test results were included in the study. They were divided into two group according to receiving anticoagulants. 
Results: 148 patients were analyzed over 1.5 years. Among them, 85 women received anticoagulant medications and 63 did not receive these treatments for the next pregnancy. Moreover, 58 out of 148 pregnant women were thrombophilic according to positive tests. Successful pregnancy outcomes were significantly higher in treated groups. The risk of abortion and unsuccessful pregnancy was significantly reduced in the treated groups. The occurrence of intrauterine fetal death (IUFD), intrauterine growth retardation (IUGR), and preeclampsia were not reduced. The use of anticoagulant during pregnancy did not have any adverse effects. The results in thrombophilia group and non-thrombophilia group demonstrated the benefit of anticoagulant therapy in improvement of pregnancy outcomes.
Conclusion: Testing for inherited thrombophilia in women who have experienced placental mediated pregnancy complications is not recommended. Anticoagulant therapy can be useful in women without thrombophilia and with poor obstetric history because of placental mediated pregnancy complications.