Changes in plasma human atrial natriuretic peptide (hANP) level in normal pregnancy and pregnancy induced hypertension.

We determined plasma human atrial natriuretic peptide (hANP) levels in normal pregnancy and pregnancy induced hypertension (PIH). The plasma hANP levels slightly decreased in the first trimester of normal pregnancy and tended to recover as pregnancy advanced, although these changes were slight. However, the plasma hANP level in puerperium was higher than that in the third trimester of normal pregnancy. The plasma hANP level in mild PIH was not significantly higher than that in the third trimester of normal pregnancy. In contrast, the plasma hANP level in three cases of severe PIH was approximately 200% higher than those in the normal third trimester and mild PIH.</p

Changes in erythrocyte deformability in normal pregnancy and pregnancy-induced hypertension, as revealed by electron spin resonance.

To study changes in hemorheologic properties during pregnancy, erythrocyte deformability was measured by an electron spin resonance (ESR) method. The results obtained by this method showed that erythrocyte deformability in normal pregnancy decreased significantly in the first trimester compared with nonpregnant controls, and continued to decrease slightly as pregnancy progressed. On the other hand, erythrocyte deformability in severe pregnancy-induced hypertension (PIH) was significantly lower than that in the third trimester of normal pregnancy. Additionally, we found that the hematocrit level needed for erythrocytes to exhibit high deformability is lower during pregnancy. These results suggest that hemodilution in normal pregnancy, so-called hydremia, compensates for the decrease in erythrocyte deformability. Conversely, since erythrocytes become less deformable in a hemoconcentration condition in severe PIH, microcirculatory disturbance of various organs, including the uteroplacental unit, may occur. The lowered erythrocyte deformability may be one of the important pathologic features in PIH.</p