High levels of reticulated platelets and thrombopoietin characterize fetalthrombopoiesis

To characterize fetal thrombopoiesis, we determined plasma thrombopoietin ( TPO) and glycocalicin levels, platelet counts and reticulated platelets (RP ) of fetuses and compared them with the respective values of their mothers. Percutaneous umbilical vein sampling in abnormal pregnancies revealed twof old higher thrombopoietin levels and 20-fold higher reticulated platelet co unts, but lower levels of glycocalicin in fetuses compared with their mothe rs (P < 0.05). Neither the expression of platelet glycoprotein Ib and IIb o n platelets nor the platelet counts were different between mothers and thei r fetuses. These data indicate enhanced thrombopoiesis and/or increased pla telet turnover in fetuses.