PLASMA VOLUME IN NORMAL FIRST PREGNANCY

Summary Serial measurements of plasma volume were made in 56 normal, healthy primigravidae at 12, 16, 20, 25, 30, 34 and 38 weeks' gestation using the Evans Blue (T‐1824) dye dilution technique with the women lying on their sides. Measurements were also made on 19 of these patients six weeks post partum. There was a progressive plasma volume expansion to a maximum between 30 to 34 weeks, with a terminal plateau. The expansion between the mean non‐pregnant volume and the mean maximum measured volume during pregnancy was 1246 ml. There was a significant relationship between plasma volume at 38 weeks' gestation and the birthweight of the baby.