Plasma volume changes in pregnancy in Indian and European primigravidae.

Serial measurements of plasma volume were made in 60 normal healthy primigravidae, 30 of European and 30 of Indian origin, matched for age. Recordings wer made at 16, 22, 28, 34 and 38 weeks gestation using the Evan's blue dye dilution technique with the women lying on their sides. A progressive increase in volume was demonstrated to a plateau between 34 and 38 weeks. The plasma volume of the European group was significantly higher at all stages. There was a significant difference in body size between the groups, and European infants had a higher mean birth weight. When plasma volume was expressed in terms of body weight, both groups gave identical results throughout pregnancy. It is unlikely that there is a constant physiological difference between the two groups that might account for differing obstetric performance.