Serial serum thrombopoietin levels in a pregnant woman with essential thrombocythaemia.

Thrombopoietin (TPO) is a ligand for c-mpl, which regulates the differentiation and maturation of megakaryocytes. Essential thrombocythaemia (ET) is a clonal myeloproliferative disorder. It has been reported that the platelet count declines during pregnancy in ET patients. We examined serial changes in the serum TPO level during the course of pregnancy in a patient with ET. The serum TPO level showed significant negative correlation with the platelet count. Although it mimicked the normal feed back system, the TPO levels were consistently higher than the normal upper limit. Accumulation of these data will be helpful in revealing the pathogenesis of ET and the decline in the platelet count during pregnancy.