The magnitude of hemoconcentration with eclampsia

Objectives: To determine the extent of hemoconcentration in nulliparous women with eclampsia.Methods:Total blood volume was measured before delivery using autologous ⁵¹chromium-tagged erythrocytes in 29 nulliparous women with eclampsia. (These studies were completed in 19581978 when such tests were not contraindicated in gravid women). This was repeated several weeks postpartum at which time all of the women had become normotensive. Blood volume determinations were then compared with those from a cohort of 44 normotensive pregnant women. Results:Eclamptic women had a mean 9 (±15) increase in blood volume at delivery compared with their mean nonpregnant blood volume. Normal pregnant women had a mean 47 (± 15) increase in blood volume compared with their nonpregnant values. In both groups, nonpregnant mean volumes were very similar (2930 ± 450 versus 3070 ± 390 mL). In 12 women with eclampsia in the index pregnancy, paired blood volume determinations were again done in the late third trimester in 14 subsequent normotensive pregnancies. This time they had a mean 45 (±17) increase compared with their nonpregnant mean blood volume (p < 0.001) which was almost identical to the 47 expansion in the normal cohort.Conclusions:Women with eclampsia have significantly decreased blood volumes at term compared with normally pregnant women. In subsequent normotensive pregnancies, blood volume expansion in these women is normal.