Deterioration in cardiac systolic and diastolic function late in normal human pregnancy

The aim of the present study was to undertake a longitudinal study of systolic and diastolic cardiac function during normal pregnancy. At a median of 16 weeks of gestation, 100 primiparous women underwent echocardiography, including tissue Doppler imaging, determining left ventricular mass, cardiac output, systolic and diastolic velocities, and wall stress. A total of 32 were assessed again at a median of 37 weeks of gestation. Non-pregnant control estimates (n=9) were obtained by averaging four separate measures over two menstrual cycles. Initially, the pregnant women had significantly higher pulse rates than controls, associated with greater ventricular wall stress (two-tailed P value=0.015), and systolic (two-tailed P value=0.005) and diastolic (two-tailed P value=0.018) lateral wall myocardial velocities, but no differences in systolic blood pressure, left ventricular mass or cardiac output. By 37 weeks of gestation, increased blood pressure (two-tailed P value<0.001) and left ventricular mass (two-tailed P value=0.002) were associated with a significant increase in ventricular wall stress (two-tailed P value<0.001), and reductions in septal systolic (two-tailed P value=0.004) and septal and lateral early diastolic (two-tailed P value<0.001) myocardial velocities. The diastolic velocities at 37 weeks correlated inversely with maternal weight and age. In conclusion, by term pregnancy, an increase in ventricular wall stress is accompanied by a deterioration in cardiac function.