Influence of head-out water immersion on plasma renin activity, aldosterone, vasopressin and blood pressure in late pregnancy toxaemia.

In 39 healthy pregnant women and 45 women with mild or moderate late pregnancy toxaemia (LPT) the influence of head-out water immersion on blood pressure, the renin-aldosterone system, vasopressin and plasma osmolality was examined. Water immersion induced a prompt and marked fall in systolic and diastolic blood pressure, which was significantly higher in LPT women. Simultaneously a significant decrease of plasma renin activity, aldosterone and vasopressin was noted both in healthy and toxaemic pregnant women. In contrast to healthy pregnant women in LPT haemodilution was not observed in the early phase of water immersion.