Anticoagulation Therapy for Pregnancy-Associated Thrombosis: A Retrospective Observational Study

Objectives: Pregnancy-associated deep vein thrombosis (DVT) is a rare disease, and data on anticoagulation therapy are lacking. The present study examined the treatment outcome with unfractionated heparin (UFH) subcutaneous injection in patients with pregnancy-associated DVT. Methods: This single-center, retrospective, observational study enrolled 15 patients with pregnancy-associated DVT treated from January 2014 to April 2021. Results: The median age was 35 years. The median gestation week at onset was 10 (interquartile range is 8-11). All patients presented with painful symptoms with edema. All patients had proximal DVT. Anticoagulation therapy using UFH was performed in 14 patients. The median continuous dose of heparin was 18,750 U/day, and the median subcutaneous dose was 20,000 U/day. During the outpatient period, the values of activated partial thromboplastin time fluctuated wildly, but the fibrin monomer complex level remained consistently low. There were two mild bleeding complications, but neither prevented the continuation of anticoagulation therapy. During delivery, thrombi were not detected in 10 of 13 patients (77%), whereas three patients (23%) exhibited regression without resolution of the thrombus. Conclusion: Anticoagulation using UFH subcutaneous injection was safely performed in patients with pregnancy-associated DVT without serious complications or progression of thrombosis.