Therefore, this study concluded that long-term use of norethisterone enanthate is not associated with any markedly deleterious effects on factors VIIc and Xc, antithrombin III or haemoglobin levels.19 The drug norethisterone enanthate, a first-generation progestogen, has a lower risk of causing venous thrombosis when compared with third-generation progestogens. Here, SERPINC1 is linked to Venous thrombosis.