[Blood coagulation and fibrinolysis activities during normal pregnancy and fetal growth--study based on estimated fetal body weight].

: There are many factors influencing the growth of the fetus. Since these factors have complex interrelations, they are difficult to clarify. The authors studied the effects of blood coagulation and fibrinolysis on the growth of the fetus during pregnancy, especially from the 2nd trimester into the 3rd trimester. The subjects were 86 normal pregnant women, and the subjects of study were blood coagulation, fibrinolysis activity of the mother, and estimated fetal birth weight after the 28th (2nd trimester) and 36th weeks of gestation (3rd trimester) in each case. 1. Changes in blood coagulation activity and fibrinolysis varied from the 2nd trimester into the 3rd trimester. The percentage of cases showing lowered platelets was 68.6% of the total, and the percentages of cases with reduced platelet ADP, epinephrine, and collagen aggregation were 60.5%, 55.8%, and 51.2%, respectively. The percentages of cases showing shortened prothrombin time and activated partial thromboplastin time were 58.1% and 51.2% of the total, respectively. The percentage of cases with reduced fibrinogen was 24.4% of the total. The percentages of cases with reduced antithrombin III, plasminogen, and alpha 2-plasmin inhibitor activity were 66.3%, 55.8%, and 75.6% of the total, respectively. 2. The birth weight of babies in a group with shortened prothrombin time was 2,935.1 +/- 395.2g(n = 50, mean +/- SD), while that in a group with prolonged prothrombin time was 3,106.2 +/- 357.9g(n = 36). The estimated fetal birth weight gain from the 2nd trimester to the 3rd trimester was 1,431.6 +/- 296.5g in the former group and 1,644.5 +/- 390.5g in the latter group. The differences were significant (p less than 0.05, p less than 0.01). The birth weight of babies in a group with lowered antithrombin III activity was 2,960.1 +/- 341.3g(n = 57), and that in an acceleration group was 3,157.8 +/- 370.0g(n = 29). The estimated fetal weight gain from the 2nd trimester to the 3rd trimester was 1,477.7 +/- 281.9g in the former group and 1,637.1 +/- 390.6g in the latter group. The differences were significant (p less than 0.02, p less than 0.05). 3. The estimated fetal weight gain from the 2nd trimester to the 3rd trimester in the group showing prolongated prothrombin time and activated partial thromboplastin time in this period was significantly larger than in the group showing shortened prothrombin time and activated partial thromboplastin time (p less than 0.001). These results suggested that the changes in blood coagulation and fibrinolysis activity of mothers from the 2nd trimester to the 3rd trimester affected the growth of the fetus.