CHANGES IN CENTRAL HEMODYNAMICS AND PERIP HERAL-CIRCULATION DURING PREGNANCY

Systemic blood pressure, stroke volume, systolic time intervals (measu red via impedance cardiography), rheological properties of blood (hema tocrit, plasma viscosity and erythrocyte aggregation) and peripheral f low conditions (measured via occlusive impedance plethysmography) were assessed longitudinally in 21 nonpregnant women and in 49 patients fr om 5th to 41st week of gestation and 4 to 9 days postpartum. Measureme nts were taken in the left lateral position. The data showed, that dz/ dt, stroke volume and cardiac index rose until the 30th week of gestat ion and decreased throughout the rest of pregnancy. The same changes w ere observed in the data on diastolic pressure and Heather Index. Peri pheral resistance fell during the first trimester and then increased n otably throughout the following time of pregnancy. The systolic time i ntervals become longer in the last trimester of pregnancy, but were ch aracterised by a markedly shortened left ventricular ejection time (LV ET). The reduction of stroke volume in the last trimester is due to di minished venous return or venous outflow by obstruction of the inferio r vena cava or by abnormalities in the left ventricular function and/o r impaired rheological properties of the blood.