Effects of hypothermia on uterine circulation and on the fetus.

Abstract

Summary1. The effects of immersion hypothermia on uterine circulation and on the fetus were investigated in shivering and non-shivering dogs. 2. Uterine blood flow decreased markedly in both groups and the fall was associated with a marked increase in uterine vascular resistance. In the shivering dogs, contraction of the uterine muscle and increase in intramural resistance are probably responsible for the fall in uterine flow. 3. Despite the uterine ischemia, fetal survival is not affected because fetal temperature falls to the same extent as that of the mother. Hypothermia of the fetus in utero probably increases its tolerance to hypoxia.