SERIAL CHANGES IN CARDIAC-OUTPUT DURING NORMAL-PREGNANCY - A DOPPLER ULTRASOUND STUDY

Objectives: To determine the direction and magnitude of change in card iac output (GO) during pregnancy. Study design: We performed serial me asurements of CO on five occasions from 24 weeks gestation to term and once during the puerperium in 26 normal pregnancies (156 measurements ) using Doppler ultrasound measurement of flow velocity profiles and a ortic root cross sectional area. Results: CO increased to 7.0 l/min by 32 weeks gestation, 49% above baseline values. It fell to 5.7 l/min b y term, 21% above baseline. The peak in CO corresponded with an increa se in heart rate to 91 beats/min, 32% above baseline. Stroke volume pe aked at 36 weeks gestation, by which time CO had already begun to decl ine. Conclusions: CO increased in a linear fashion until 32 weeks gest ation and then declined to term, but to a value still greater than the postpartum baseline. These findings have obvious management implicati ons for patients with serious heart disease complicating pregnancy. Co pyright (C) 1996 Elsevier Science Ireland Ltd.