Endothelin-1 activity in pregnancy.

Plasma endothelin-1 activity was measured by radioimmunoassay in 24 normotensive non-pregnant women and in 24 normotensive pregnant, 24-aproteinuric hypertensive and 24 pre-eclamptic women. Endothelin-1 activity was increased in the pre-eclamptic group (2.7 +/- 06 pg/ml) compared to the normotensive non-pregnant (1.0 +/- 0.8 pg/ml; P < 0.0001), normotensive pregnant (1.2 +/- 0.4 pg/ml; P < 0.0001) group and the aproteinuric hypertensive group (1.4 +/- 0.7 pg/ml; P < 0.0001). There was no difference in endothelin-1 activity between the normotensive non-pregnant and normotensive pregnant group (1.0 +/- 0.8 vs. 1.2 +/- 0.4 pg/ml; P = 0.3). However, there was a difference between the aproteinuric hypertensive group (1.4 +/- 0.7 pg/ml) and both the normotensive nonpregnant (1.0 +/- 0.8 pg/ml; P < 0.01) and the normotensive pregnant group (1.2 +/- 0.4 pg/ml; P < 0.06). The birth weight in the pre-eclamptic group (2.48 +/- 0.61 kg) was significantly lower than that of the normotensive pregnant group (2.85 +/- 0.33 kg; P < 0.001) and the aproteinuric hypertensive group (2.99 +/- 0.46 kg; P < 0.001). In addition, there was no difference in birth weight between the normotensive pregnant group and aproteinuric hypertensive group (2.85 +/- 0.33 vs. 2.99 +/- 0.46 kg; P = 0.3). A significant Pearson's correlation of plasma endothelin-l versus birth weight in the pre-eclamptic group was obtained (r = 0.64; P < 0.0001). Endothelin-1 activity is increased with pre-eclampsia in black African women with pre-eclampsia. The results of our study also suggests an ethnic difference in plasma endothelin-1 activity when compared to result of studies carried out in Caucasian women with hypertensive disorders of pregnancy.