Effect of the supine position on uterine and umbilical blood flow during the third trimester of uncomplicated pregnancies in multiparous patients

We established the effects of the supine position on umbilical blood flow when measured during the third trimester in 30 multiparous, normotensive patients. Blood flow in the umbilical and uterine arteries and blood pressure in the brachial and popliteal arteries were blindly taken by two different observers: first in the lateral and 5 min later in the supine position. There was a significant difference in mean blood pressure between the two postures. However, there was no statistical difference in the pulse pressure or in systolic/diastolic ratio in the umbilical and uterine arteries between the two positions. Postural changes in normotensive multiparous patients do not affect uterine and umbilical blood flow during the third trimester of uncomplicated pregnancies.