High Plasma Concentrations of Human Atrial Natriuretic Polypeptide in Women with Pregnancy-Induced Hypertension

Abstract

Unextracted plasma concentrations of human atrial natriuretic polypeptide (hANP) in 32 normotensive term pregnancies and 18 term pregnancies with pregnancy-induced hypertension (PIH) were measured by kit radioimmunoassay. The mean basal plasma hANP concentration was 299 ± 46 (X ± SD) pg/ml in uncomplicated term pregnancies and 378 ± 75 pg/ml in women with PIH (p < 0.001). Furthermore, two subsets of patients with PIH could be identified on the basis of hANP alone and not on clinical parameters. In one subset, seven PIH patients exhibited hANP concentrations within the 95% confidence limits of uncomplicated pregnancy hANP concentrations, while another subset of 11 hypertensive patients demonstrated markedly elevated hANP (436 ± 53 pg/ml). Maternal age, parity, fetal weight, and gestational age did not affect hANP concentrations in normal term pregnancies. These results suggest that: 1) hANP concentrations do not change during normal pregnancy; 2) are significantly elevated in patients with PIH at term; 3) can differentiate between PIH subpopulations; and 4) may serve as a marker and/or regulator of PIH