Frequency of thrombophilia-associated mutations and polymorphisms in pregnant women with a history of thrombosis or pregnancy complications

Objectives: To assess the frequency of multiple thrombophilia-associated mutations and polymorphisms in a selected population of high-risk pregnancies. Methods: Thrombophilia screening was performed for 1,500 pregnant women with prior pregnancy complications or thrombotic events. Nine thrombophilia-associated mutations or polymorphisms were screened: factor V Leiden, factor V H1299R, prothrombin G20210A, MTHFR C677T, MTHFR A1298C, factor XIII V34L, PAI-1 4G/5G polymorphisms, EPCR G4600A, EPCR C4678G. Results: Out of the 1,500 patients, 1,291 fulfilled the criteria for data interpretation. All patients had low-risk thrombophilia-associated genetic variants. Only 1.24 % of cases presented high-risk abnormalities (homozygous factor V Leiden/prothrombin G20210A, or both mutations in heterozygous form). Heterozygous factor V Leiden occurred in 10.38 % of cases, while only 5.81 % carried heterozygous prothrombin G20210A mutation. The frequency of prothrombin G20210A mutation was higher (10.37 %) in the subgroup associating factor V Leiden, than in the subgroup lacking it (5.36 %). Low-risk genetic variants occurred with a higher frequency: 23.78 % factor V H1299R, 57.32 % MTHFR C677T, 55.54 % MTHFR A1298C, 44.07 % factor XIII V34L, 73.20 % PAI-1 4G/5G polymorphisms, 69.64 % EPCR G4600A, and 69.63 % EPCR C4678G. Conclusions: All patients had at least one prothrombotic genetic mutation or variant. Our data highlight the need for thrombophilia screening, including low-risk genetic variants, in a high-risk population of pregnant women with a history of pregnancy complications or thrombotic events.