A possible explanation for nocturnal hypertension in preeclamptics

Abstract

To assess the pathophysiology of nocturnal hypertension in preeclamptics, diurnal changes in thermal conductivity of the skin, and blood pressure were studied in normal pregnant and preeclamptic subjects from 28 weeks of gestation onward. Changes of thermal conductivity of the skin were measured using the zero-heat flow method. In all preeclamptics with nocturnal hypertension, thermal conductivity of the skin in the night-time increased significantly compared to that during the day, though there was no change between the night- and day-time in the normal pregnant subjects. Heart rate did not change in any subject with preeclampsia. Evidence that the increase in thermal conductivity in the skin and the elevation of blood pressure occurred simulta- neously during the night suggested that nocturnal hypertension in preeclamptics may relate to increases in circulating plasma volume.

Key Words:

• Microcirculation
• Thermal conductivity
• Preeclampsia
• Nocturnal hypertension