Correlation between Grade III Placenta and Plasma Antithrombin III Activity in Full Term Pregnancy

Abstract

We evaluated whether the presence of a grade III placenta correlates with blood hypercoagulability in pregnancy between 37 and 39 weeks of gestation. The placenta was graded by ultrasound in 155 healthy full-term women and the plasma levels of antithrombin III (AT III) activity, thrombin-antithrombin complex (TAT) and D-dimer were correlated with each placental grade. AT III activity levels tended to decrease with advancing placental grade from I to III (p < 0.05). D-dimer showed the same tendency while TAT did not. The incidence of reduced AT III activity levels (<70%) in women with a grade III placenta was about twice those in women with a grade II or I placenta, and that of AT III <80% was 3-fold greater. We concluded that the presence of a grade III placenta in full-term pregnancies correlates with blood hypercoagulability.

Longitudinal evaluation of markers of hemostasis in pregnancy

“…In their studies, Clark and Bremme found a modest decrease in antithrombin III levels at term (12,17). Asakura found a slight decrease in antithrombin III during the third trimester and this decrease was associated with fi brinous layers found in placenta (18). Our study failed to detect a signifi cant decrease in antithrombin III.…”

Pregnancy and Hemostasis: From Physiology to Pathological States

“…This decrease is the witness of an activation of coagulation, with physiological formation of placental intervillous thrombosis. [12] The evolution of protein C (PC) is variable depending on the term, an increased rate in the second trimester, followed by a decrease in the third, and then a new increase in the immediate postpartum. [13] Conversely, there is a gradual and significant decrease in protein S (PS), close to 50% at term and persisting for 2 months in the postpartum, longer in the case of breastfeeding, and the concentration of PS is hormonally sensitive.…”