Atrial natriuretic factor maternal and fetal concentrations in severe preeclampsia.

There is a reduction in intravascular volume in patients with preeclampsia. Since the secretion of atrial natriuretic factor by human atrial myocytes is stimulated by increased intraatrial pressure or atrial distention, we sought to determine whether circulating maternal plasma atrial natriuretic factor concentrations were lower in patients with preeclampsia compared to normal pregnant women. The level of alpha-human atrial natriuretic factor was measured by a specific radioimmunoassay. Maternal venous concentrations of a alpha-human atrial natriuretic factor were higher in patients with severe preeclampsia (116.12 +/- 13.37 pg/ml) than in normal pregnant women (80.30 +/- 4.02 pg/ml). Umbilical artery alpha-human atrial natriuretic factor concentrations were higher in fetuses born to patients with severe preeclampsia (197.68 +/- 29.10 pg/ml) than normal control subjects (118.00 +/- 12.52 pg/ml). Umbilical artery alpha-human atrial natriuretic factor concentrations were higher than umbilical or maternal venous concentrations. In cases of severe preeclampsia, despite the presumed volume changes, maternal atrial natriuretic factor concentrations are higher than in normal pregnant women. The fetus appears to produce its own atrial natriuretic factor. Umbilical artery atrial natriuretic factor concentrations in fetuses born to preeclamptic mothers are higher than those seen in normal control subjects.