Abstract: Objective A variety of maternal physiological changes occur during pregnancy, including coagulation systems. There is a hypercoagulability state in normal pregnancy, which is beneficial in preventing excessive blood loss at the time of delivery; which can also induce during pregnancy the risk of pre-DIC state. The aim of this study is to explore the dynamic changes and clinical significance of plasma antithrombin-Ⅲ(AT-Ⅲ) and P-selectin(GMP-140) during different stages of normal pregnancy.Methods A prospective case controlled study was carried out. Eighty-five healthy pregnant women were investigated at first, second and third trimesters respectively as experimental groups and fifty healthy age-matched non-pregnant women as a control group were also investigated. Antithrombin-Ⅲ was determined by chromogenic substrate method. P-selectin was detected by enzyme linked immunoadsorbent assay(ELISA).Results The AT-Ⅲ level was higher in pregnant women in the first trimester(146.37±27.44)μg/L than that in the control group(122.43±31.81)μg/L(P<0.001), while the activities of AT-Ⅲ was obviously decreased in pregnant women in the second(26.02±30.39)μg/L and third trimesters(125.43±21.89)μg/L as compared with that in the first trimester(P<0.05). GMP-140 levels of first, second and third trimester groups were (93.36±38.66)μg/L, (71.01±64.69)μg/L and (123.32±75.36)μg/L respectively. The level of GMP-140 was lower in pregnant women in the first trimester than that in the control group(97.76±45.83)μg/L, being significantly lower in the second group(P<0.05). While, the activities of GMP-140 had an obviously higher level in the third trimester than those in other groups(P<0.01).Conclusion Hypercoagulability has been observed in the pregnant women since the second trimester, and the changes are more significant with the progress of pregnancy.

Key words: pregnancy, antithrombin, P-selectin