Hemostatic parameters and platelet activation by flow-cytometry in normal pregnancy: a longitudinal study

Abstract

Nineteen pregnant women with uncomplicated pregnancies were studied during the first, second, and third trimesters. We measured the following hemostatic parameters: prothrombin time, activated partial thromboplastin time, fibrinogen, antithrombin III, protein C, protein S, platelet number and volume. Platelet function was examined by a cytofluorimetric method, using an anti-GPM-140 antibody which is directed against a platelet alpha granule membrane protein. Activated platelets were expressed as a percentage of the GMP-140-positive platelets over total platelets. Fibrinogen levels showed a steady increase during pregnancy; conversely prothrombin time, activated partial thromboplastin time, protein C, and antithrombin III showed no significant modifications and remained within the reference range. There was a decrease of protein S activity throughout pregnancy, although protein S antigen did not follow this trend. The decrease occurred early in pregnancy and persisted during the second and third trimesters, reaching a stable plateau. We observed no platelet volume change or activation: the percentage of activated platelets was within the normal reference range, even in late pregnancy.

Physiological Changes in Hematological Parameters During Pregnancy

“…Leucocytosis, occurring during pregnancy is due to the physiologic stress induced by the pregnant state [8]. Neutrophils are the major type of leucocytes on differential counts [9,10]. This is likely due to impaired neutrophilic apoptosis in pregnancy [9].…”

“…Neutrophils are the major type of leucocytes on differential counts [9,10]. This is likely due to impaired neutrophilic apoptosis in pregnancy [9]. The neutrophil cytoplasm shows toxic granulation.…”

Establishing a normal range for d‐dimer levels through pregnancy to aid in the diagnosis of pulmonary embolism and deep vein thrombosis

“…It was felt that testing the same women would be a statistically more accurate way of showing any significant changes in D-dimer levels and for establishing a normal range up to 16, 26 and 34 weeks, thus accounting for the hypercoaguable changes previously noted in pregnancy [11]. The normal D-dimer level at this hospital is < 280 ng mL…”

Platelet aggregation in citrated whole blood of the first trimester of pregnancy

“…Early studies regarding platelet parameters in pregnancy suggested enhanced platelet destruction accompanied by increased platelet production [11][12][13][14]. However, previous studies examining platelet activation during normal pregnancy yielded conflicting results-some reported increased activation [13,15,16], while others reported no change [17,18]. In addition, a recent report suggested that platelet reactivity to collagen was significantly reduced during the first trimester of pregnancy compared with that in non-pregnant controls [19].…”