Venous and arterial behavior during normal pregnancy

1 Department of Anesthesiology, A. Béclère Hospital, 92140 Clamart; and 2 Department of Internal Medicine (Medicine 1) and Institut National de la Santé et de la Recherche Médicale, U 337, Broussais Hospital, 75674 Paris Cedex 14, France To assess the contribution of the arterial and venous systems in the hemodynamic changes of normal pregnancy, we studied blood flow, vascular resistance, venous tone, and the viscoelastic properties ("creep") of the upper and lower limbs (using plethysmography), aortic distensibility (using pulse wave velocity measurements), and cardiac dimensions (using echocardiography) in nine healthy women. Studies were longitudinally performed at the first (10-13 wk) and third (33-38 wk) trimesters of pregnancy in comparison with the period between the third and sixth month after delivery. From the first trimester, heart rate significantly increased while systemic blood pressure and limb vascular resistances did not change significantly and aortic distensibility increased ( P < 0.05). Lower limb viscoelastic properties decreased at the third trimester ( P