Plasma volume determination in normal and preeclamptic pregnancies.

To determine the clinical usefulness of plasma volume determinations, we measured plasma volume serially throughout pregnancy with the use of the Evans blue dye-dilution technique in 20 subjects with normal pregnancies. In comparison, four preeclamptic subjects were studied. In preeclamptic subjects compared to normal subjects, plasma volume was reduced (1763 +/- 216 versus 2345 +/- 198 ml/m2, p less than 0.001). Two normotensive subjects who subsequently developed preeclampsia had reduced plasma volumes prior to the onset of hypertension as compared to volumes in those who remained normotensive (1918 +/- 86 versus 2345 +/- 198 ml/m2, p less than 0.01). Those subjects who were delivered of infants who were small for gestational age had significantly reduced plasma volumes compared to volumes of those who were delivered of infants who were appropriate for gestational age (1950 +/- 333 versus 2237 +/- 259 ml/m2, p less than 0.05), but this was true only among gravid women with pregnancies complicated by preeclampsia. We conclude that failure of plasma volume expansion is associated with the development of preeclampsia and also intrauterine fetal growth retardation in preeclamptic subjects.