First trimester maternal concentrations of thrombin-inhibitor complexes and the presence of histologic placental lesions at delivery

Abstract

Objective. Placental fetal vessel thrombosis or vasculitis and retroplacental hematoma have been associated with adverse neonatal outcomes. The activation of thrombin may contribute to the development of thrombosis and inflammation, and can be assessed through the measurement of thrombin-inhibitor complexes.

Methods. A nested case–control study was performed within a cohort of women with singleton gestations. Thrombin–antithrombin III (TAT) and Thrombin-Heparin co-factor II (T-HCII) concentrations were measured in first trimester maternal plasma. Cases were defined by retroplacental hematoma and/or fetal vessel thrombosis or vasculitis in the umbilical cord or chorionic plate. Outcomes were analysed with Mann–Whitney U and linear regression.

Results. Concentrations of both TAT (p = 0.013) and T-HCII (p = 0.001) from maternal plasma was significantly lower in cases than in controls.

Conclusions. The development of placental inflammatory and thrombotic lesions at term may be associated with lower concentrations of thrombin-inhibitor complexes earlier in the pregnancy.

Keywords:

• Fetal vessel thrombosis
• fetal vessel vasculitis
• thrombin–antithrombin
• heparin co-factor II
• retroplacental hematoma