HEMODYNAMICS AT REST AND DURING EXERCISE IN NORMAL PREGNANCY AS STUDIED BY CARDIAC CATHETERIZATION 12

Abstract

Cardiac catheterization in 44 normal pregnant women at various stages of pregnancy revealed a maximum increase of 42% in cardiac output compared with nonpregnant controls. Peak values were found at the 25-27th weeks with a fall to normal prior to term. Changes in stroke volume paralleled those in cardiac output while arteriovenous O2 difference varied reciprocally (lowest mean value 3.4 volumes %). Systemic arterial pressures were not significantly changed hence calculated total peripheral resistance was decreased at the period of maximum cardiac output with return to normal prior to parturition. Cardiac output response to exercise was normal at all stages of gestation. Pressures in the right heart and pulmonary artery were only slightly increased without significant elevation above normal. Right ventricular end diastolic pressure was elevated in 6 of 27 patients at rest in the 25-35th weeks of gestation.