Efficacy of antithrombin replacement therapy in severe early-onset preeclampsia

It has been suggested that the hypercoagulable state in severe preeclampsia is strongly related to the onset of intrauterine growth retardation (IUGR) through the deterioration of placental circulation. In this study, one of two kinds of anticoagulants, heparin or antithrombin (AT), was given to severe early-onset preeclamptic women (onset before 32 weeks of gestation) with IUGR, and the efficacies in maternal and fetal findings were compared. The mechanism of AT to improve placental circulation was discussed based on our previous study using the culture system of chorionic trophoblastic cells. The mean systolic blood pressure decreased significantly in the AT group (AT concentrate 1,500 IU/d for 7 days, n = 15). Fetal growth was calculated by ultrasonographic measurement, and the weight gain was higher in the AT group than it was in the heparin group. In vitro experiments showed that AT increased the thrombomodulin (TM) antigen on the cell surface and also increased prostaglandin I2 (PGI2) production by cultured trophoblastic cells. This suggests that AT replacement therapy is useful for improving maternal hypertension and fetal findings in severe preeclampsia with IUGR through the increase of TM and PGI2 production in both maternal and placental circulation.