A long-term retrospective study of young women with essential thrombocythemia.

Objective: To describe presenting clinical manifestations, long-term disease complications, prognostic indicators, and outcome of pregnancy for women younger than 50 years with essential thrombocythemia.

Patients And Methods: We retrospectively reviewed the records of all patients with essential thrombocythemia evaluated at Mayo Clinic, Rochester, Minn, between 1969 and 1991 and identified 74 young women (median age, 35 years; range, 18-48 years) with essential thrombocythemia. The diagnosis was based on previously established criteria. Median follow-up was 9.2 years (range, 0.2-26.2 years).

Results: Overall survival was similar to that of an age- and sex-matched control population. Thrombotic events (except superficial thrombophlebitis) occurred at and after diagnosis in 11 patients (15%) and 13 patients (18%), respectively. A history of thrombosis at diagnosis was significantly associated with recurrent thrombosis (P = .03). A platelet count higher than 1500 x 10(9)/L at diagnosis was significantly associated with gastrointestinal tract bleeding and subsequent development of venous (but not arterial) thrombosis (P = .04). Major hemorrhagic events occurred in only 3 patients (4%) after diagnosis. Only 1 patient developed acute leukemia. Thirty-four pregnancies occurred in 18 patients. Of these, 17 (50%) resulted in live births. Of the 17 patients with unsuccessful pregnancies, 14 had spontaneous abortions, 1 had an ectopic pregnancy, and 2 had elective abortions. Preconception platelet count, thrombotic history, or specific therapy was not useful in predicting pregnancy outcome.

Conclusion: Young women with essential thrombocythemia can expect long survival with a low incidence of life-threatening thrombohemorrhagic complications or acute leukemia. There is an increased incidence of first-trimester miscarriages that may not be influenced by specific therapy.