Intravascular volume determinations and fetal outcome in hypertensive diseases of pregnancy.

With the Evans blue technique, 178 plasma volume, blood volume, and red cell volume determinations were studied in 51 hypertensive and 35 normotensive gravidas. Hypertensive pregnancies were classified according to the American Committee on Maternal Welfare schema. A large range and overlap in plasma and blood volume determinations was found, but mean values in patients with hypertensive disease were significantly depressed when compared with normotensive gravidas. A decrease in red cell mass was observed only in the severe hypertensive group of women. In general, those hypertensive patients with plasma and blood volume determinations approaching those of the normotensive control patients were associated with a favorable maternal and fetal outcome. Extreme hypovolemia occurred in most pregnancies associated with severe hypertensive disease and evidence of uteroplacental insufficiency.