Cardiac function at term in human pregnancy

Objectives: We have previously demonstrated deterioration in cardiac function at term in human pregnancy. To explore further, we investigated central arterial hemodynamics and association with maternal weight during gestation. Study design: Primiparous women (n = 32) were recruited in a tertiary referral obstetric hospital and a longitudinal cohort study with analyses at median 16 and 37 weeks gestation undertaken. Subgroups of normal body mass index, <25 kg/m ², and overweight, ≥25 kg/m ², at 16 weeks were created. Main outcome measures: We performed 2D speckle tracking echocardiography strain analysis and tonometric measures of central arterial pressures, waveforms and pulse wave velocity. Results: A reduction in cardiac strain (2P = 0.002) from 16 to 37 weeks gestation was associated with increased systemic vascular resistance (2P = 0.008), reduced arterial compliance (2P = 0.004) and increased central arterial pressures (2P < 0.001) and augmentation index (2P = 0.001). Conclusions: By 37 weeks, compared with values in earlier pregnancy, overweight women had higher systemic vascular resistance (2P < 0.05). Additionally, their central diastolic pressure was higher (2P < 0.05) and their ventricular strain was lower (2P < 0.05) than in normal weight pregnant women. An increase in systemic vascular resistance and central arterial pressures by term may contribute to the observed deterioration in cardiac function. This appears more prominent in overweight women.