Objective: We investigated whether ascites samples obtained from pregnant women during cesarean sections contained antithrombin because it is unknown whether antithrombin escapes from the blood and passes into the interstitial space during pregnancy.
Methods: The concentration and activity levels of antithrombin were determined in six ascites samples obtained from six consecutive women who exhibited generalized edema, ascites, and a gradual decline in antithrombin activity.
Results: All six ascites samples contained antithrombin (mean +/- SD, 4.9 +/- 2.2 mg/dL; range, 2.7-8.8 mg/dL) and exhibited an antithrombin activity level of 15.5 +/- 6.0% (range, 10-24%).
Conclusions: Antithrombin escapes from the blood into the interstitial space in pregnant women. This phenomenon partially explains the gradual decline in antithrombin activity observed in these six pregnant women with generalized edema and large volumes of ascites.