He risk of thrombosis in asymptomatic low riskThe therapeutic options include antithrombotic treatment and cytoreductive agents. Low dose aspirin is safe during pregnancy. However, demonstration of a significantly better outcome of pregnancies evolving under continuous aspirin treatment has not been confirmed by a recent report [6]. Some studies have suggested that aspirin from the onset of pregnancy plus heparin from the second trimester might improve pregnancy outcome [79].Page 10 of(page number not for citation purposes)Orphanet Journal of Rare Diseases 2007, 2:http://www.OJRD.com/content/2/1/Many pregnancies in ET have a successful outcome with minimal therapy. Cytoreductive treatment should preferably be avoided during pregnancy, especially during the first PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/28607003 trimester. None of the agents currently used for cytoreduction in ET has a product purchase PD0325901 license for use in pregnancy. As IFN- does not cross the placental barrier, it is a potential therapeutic solution when platelet reduction is required for high risk ET pregnant patients. A small number of publications is available, showing, up to now, no toxicity for the fetus [5,80]. Breast feeding is however not recommended during cytoreductive treatment including IFN-. Several retrospective analyses have also led authors to suggest that reducing the platelet number using IFN- for patients with prior pregnancy events might improve the chance of a successful outcome in subsequent pregnancies. When ET has been already diagnosed, some important issues concerning the risk of pregnancy should be discussed before conception. For ET female already treated with HU, a wash-out period of 3 months has been recommended. However, for pregnancies where HU had been used during a more or less limited period of time, the toxicity of the product is probably less than it might be anticipated. Anesthetists prefer aspirin to be stopped two weeks before delivery, to prevent the risk of hematoma after epidural and spinal anesthesia. Low molecular weight heparin (LMWH) is given as an alternative to aspirin. The greatest risk for thromboembolism is post partum and prophylaxis, usually in the form of aspirin and LMWH, should be continued for several weeks.nosis, the overall survival was similar to that of an ageand sex-matched control population, with a low incidence of life-threatening thrombohemorrhagic complications or acute leukemia but an increased incidence of first trimester miscarriages [83]. Due to the heterogeneity of the disease, suggested by these prognostic discrepancies, efforts toward understanding the risk of hemostatic complications in ET patients, as well as the risk factors involved in the clonal progression toward PV, IMF, myelodysplasia and acute leukemia have been attempted for a long time.Risk of thrombosis The Cortelazzo study [84] in a cohort of 100 historical patients with ET has shown that the overall risk of thrombosis was equal to 6.6 patients/year compared to 1.2 control individuals/year. Three important risk factors were identified by this study. The risk of thrombosis increases with age (1.7 patients/year before 40 years; 6.3 patients/year between 40 and 60; 15.1 patients/ year after 60 years). A previous history of vascular occlusive episode increases the incidence of thrombosis from 3.4 to 31.4 patients/year. Patient’s exposure time to elevated platelet number was also, in this study, predictive for the risk of thrombosis, however no document has ever demonstrated proportionality.
