Background. Urinary 11-dehydrothromboxane B2/creatinine (11-DTXB2/Cr) is a marker for in vivo platelet activation and vascular constriction, blood thrombomodulin (TM) for endothelial damage and associated thrombosis, thrombin–antithrombin complex (TAT) for thrombin formation, and β-thromboglobulin (β-TG) and platelet factor 4 (PF-4) for in vivo platelet activation and releasing reaction. Little is known about the quantitative relationship among them during pregnancy. The present study investigated levels of five markers at different stages of normotensive pregnancy.
Methods. Subjects were 17 healthy non-pregnant women (Group 1, control) and 67 women carrying single fetuses in normotensive pregnancy. Of the pregnant women, 17 were in the 20th week of gestation (Group 2), 20 were in their 30th week (Group 3), and 30 were in their 36th week (Group 4). Urinary and circulating blood levels of 11-DTXB2/Cr, TM, TAT, β-TG, and PF-4 were measured simultaneously.
Results. The 11-DTXB2/Cr and TAT levels showed elevated values at the 20th and 30th weeks of gestation, and markedly elevated values at the 36th week, whereas the TM level remained constant throughout pregnancy. The β-TG and PF-4 levels maintained stable values at the 20th week, but showed elevated values at the 30th and 36th weeks.
Conclusions. Platelet aggregation, vascular constriction, and thrombin formation (detected by 11-DTXB2/Cr and TAT) appear to be enhanced as early as the 20th week of gestation, continuously enhanced by the 30th week, and markedly enhanced by the 36th week. Platelet activation and releasing reaction (determined by β-TG and PF-4) gradually enhanced from the 30th to 36th weeks. In contrast, endothelial damage and associated thrombosis (detected by TM) were minimal throughout pregnancy. Investigating these markers of hemostasis and endothelial function in normotensive pregnancy may provide insights into related disease states.