An effective anticoagulation is critical in pregnant patients with prosthetic heart valves. Inherited disorders may interfere with the coagulation cascade and may be associated with obstetrical complications as well as with prosthetic valve-derived complications. The patient in the present case had a history of recurrent prosthetic heart valve thrombosis (PHVT) despite an effective anticoagulation. She underwent a thrombolysis with low-dose prolonged infusion of tissue-type plasminogen activator for the management of her recurrrent prosthetic valve thrombosis. The genetic testing showed homozygous mutations of methylenetetrahydrofolate reductase (MTHFR) A 1298 C and heterozygous mutations of B-fibrinogen 455 G-A. Inherited disorders such as MTHFR A 1298 C and fibrinogen 455G/A polymorphisms may be involved in the pathogenesis of recurrent PHVT and/or pregnancy loss.