Association of Antithrombin Activity with Plasma Aldosterone Concentration and Plasma Renin Activity in Pregnant Women

Abstract

OBJECTIVE:To test the hypothesis that the blood antithrombin (AT) activity is correlated with the plasma aldosterone concentration (PAC), the plasma renin activity (PRA), and/or the PAC-to-PRA ratio during the late stage of pregnancy. METHODS:The AT activity, PAC, and PRA were determined within 7 days prior to delivery in 47 women, consisting of 30 normotensive and 6 hypertensive women with singleton pregnancies and 11 normotensive women with twin pregnancies. RESULTS:The median values of the 47 women were 86% of the normal activity level for the AT activity, 442 pg/ml for the PAC, 3.7 ng/ml/h for the PRA, and 108 pg/ml per ng/ml/h for the PAC-to-PRA ratio. Women with an AT activity ≤ 86% had a significantly lower PRA and a higher PAC-to-PRA ratio than women with an AT activity > 86% (3.5 ± 3.0 vs. 6.6 ± 4.7 ng/ml/h for PRA, P=0.008; 156 ± 109 vs. 97 ± 46 pg/ml per ng/h for PAC-to-PRA ratio, P= 0.021). The AT activity was significantly correlated positively with the PRA and negatively with the PAC-to-PRA ratio. CONCLUSIONS:The existence of a common pathophysiological background between a reduced AT activity and a reduced PRA during the late stage of pregnancy was suggested.