['To describe the trend of intracellular sodium in patients who develop preeclampsia.', 'In this longitudinal study, we determined intraerythrocyte sodium (Nai) in 303 primigravid pregnancies every fourth week from gestational week 10 through week 38. The study group included 274 normotensive and 29 chronic hypertensive gravidae. During the study, 26 normotensive and six chronic hypertensive pregnant women developed preeclampsia.', 'Chronic hypertensives showed higher baseline intraerythrocyte sodium, compared to the normotensives. The women who developed preeclampsia demonstrated a significant increase in Nai concentration from 26-30 weeks onward. Data from blood pressure recordings paralleled data from Nai.'] Does the trend of erythrocyte sodium parallel the pattern of diastolic blood pressure in preeclampsia?