Objective: To test the hypothesis of the existence of a relationship between central and peripheral hemodynamic parameters by the longitudinal evaluation of maternal echocardiographic and uteroplacental resistance modifications during normal pregnancy.
Methods: Forty-three healthy normotensive primigravidae were evaluated at 12 +/- 1, 21 +/- 1, and 33 +/- 1 weeks of gestation with uterine artery color Doppler and maternal echocardiographic examinations to identify morphologic, systolic, and diastolic variables.
Results: Cardiac output and stroke volume significantly increased during pregnancy. Uterine resistance index (RI) decreased from the first to the second trimesters (0.72 +/- 0.10 versus 0.54 +/- 0.09, P < 0.001). Left atrial dimensions increased during pregnancy (33.8 +/- 1.9 cm, 38.1 +/- 1.8 cm, 39.3 +/- 2.1 cm, P < 0.001). Left atrial function also increased. Left ventricular mass increased (132 +/- 18 g, 162 +/- 16 g, 174 +/- 27 g, P < 0.001). Diastolic function parameters showed significant modifications: E wave velocity and E/A ratio decreased; A wave velocity and deceleration time of the E wave (DtE) increased; the left ventricular isovolumetric relaxation time (IVRT) decreased significantly (88.7 +/- 6.7 ms, 75.6 +/- 7.7 ms, 71.1 +/- 5.0 ms, P < 0.001) showing a correlation with left atrial dimensions and RI (r = -0.38, r = 0.47, respectively; P < 0.001).
Conclusions: Diastolic cardiac function varies during pregnancy. A relationship between preload (left atrial enlargement), afterload (RI reduction), morphologic, and diastolic function modifications (IVRT reduction, DtE prolongation) appears to exist as a consequence of the hemodynamic modifications which occur during physiologic pregnancy. Diastolic function analysis maybe useful to identify women who fully adapt to pregnancy, and to understand the mechanisms that might be involved in women who show abnormal uterine artery Doppler waveforms.