Circadian Variations of Plasma Colloid Osmotic Pressure During the Third Trimester in Normal and Preeclamptic Pregnancies

Abstract

The present study was performed to assess the changes of plasma colloid osmotic pressure (COP) in preeclampsia, and to clarify the character of circadian variations of plasma COP in preeclampsia. During the third trimester of a normal pregnancy, plasma COP values were 21.0 ± 0.2 at 28-31 weeks' gestation, 19.3 ± 0.5 at 32-35 weeks' gestation and 20.4 ± 0.5 mmHg at 36 weeks or more of gestation. These values were significantly lower than those in normal non-pregnant subjects (23.5 ± 0.6). In preeclampsia, plasma COP values (14.7 ± 0.4) were significantly lower than those in normal pregnancy. A circadian variation of plasma COP confirmed a clear circadian rhythm with the acrophase at afternoon in all subjects, and there were no differences among normal non-pregnant, pregnant and severe preeclamptic women. These results indicate that circadian variations of plasma COP are not influenced by either pregnancy or preeclampsia, though plasma COP in preeclampsia significantly decreases.