Plasma beta-thromboglobulin in normal pregnancy and pregnancy-induced hypertension.

Plasma beta-thromboglobulin (BTG) was measured in 25 patients with pregnancy-induced hypertension (PIH), 7 of whom had severe PIH, and in 23 healthy gravidae. Also platelet counts, spontaneous platelet aggregation in vitro, and coagulation studies such as fibrinogen, fibrinogen degradation products and antithrombin III (AT III) were carried out: fetal outcome was judged by birthweight, placental weight and venous umbilical pH. Plasma BTG values of the PIH and severe PIH patients were significantly higher than those of the controls (P less than 0.05), suggesting enhanced platelet activation in the former. Compared with the controls, the entire PIH group was found to have significantly lower AT III values (P less than 0.05), more positive protamine sulphate tests (P less than 0.025), and higher plasma urate concentrations (P less than 0.01), but increased BTG values were more often observed than abnormal coagulation tests. No relationship could be demonstrated between the BTG level and fetal outcome. The significant increase in plasma BTG in PIH indicates enhanced platelet activation in these patients.