Effect of daily immersion on the edema of pregnancy.

Abstract

To evaluate whether pregnant women become refractory to the effects of immersion, we studied 11 healthy women from 26 to 38 weeks' gestation, immersed in 34 degrees C shoulder-deep water for 4 or 5 consecutive days. The daily immersion diuresis showed no change throughout the study (p = 0.98: mean, 145 ml, 159 ml, 159 ml, 173 ml, 184 ml, day 1 through day 5, respectively). The range of urine volumes was broad, 35 to 675 ml, depending on the subject's degree of edema. Immersion produced a significantly larger diuresis compared with preimmersion values, 162 ml versus 110 ml. Maternal blood pressure and heart rate consistently fell during immersion, and this effect was maintained for each day studied. The subjects' hematocrit, hemoglobin, and total protein were unchanged from a preimmersion sample on day 1 to a postimmersion sample on the last day of the study. The results of this study indicate that pregnant women do not become refractory to the hemodynamic and diuretic effects of immersion.