Effect of Passive Leg Raising on Systemic Hemodynamics of Pregnant Women: A Dynamic Assessment of Maternal Cardiovascular Function at 22-24 Weeks of Gestation

Objective: To investigate functional hemodynamic response to passive leg raising in healthy pregnant women and compare it with non-pregnant controls. Materials and Methods: This was a prospective cross-sectional study with a case-control design. A total of 108 healthy pregnant women at 22-24 weeks of gestation and 54 non-pregnant women were included. Cardiac function and systemic hemodynamics were studied at baseline and 90 seconds after passive leg raising using non-invasive impedance cardiography. Main outcome measures: Trends and magnitudes of changes in impedance cardiography derived parameters of cardiac function and systemic hemodynamics caused by passive leg raising, and preload responsiveness defined as >10% increase in stroke volume or cardiac output after passive leg raising compared to baseline. Results: The hemodynamic parameters in both pregnant and non-pregnant women changed significantly during passive leg raising compared to baseline, but the magnitude and trend of change was similar in both groups. The stroke volume increased both in pregnant (p = 0.042) and non-pregnant (p = 0.018) women, whereas the blood pressure and systemic vascular resistance decreased (p < 0.001) following passive leg raising in both groups. Only 14.8% of pregnant women and 18.5% of non-pregnant women were preload responsive and the difference between groups was not significant (p = 0.705). Conclusion: Static measures of cardiovascular status are different between healthy pregnant and non-pregnant women, but the physiological response to passive leg raising is similar and not modified by pregnancy at 22-24 weeks of gestation. Whether physiological response to passive leg raising is different in earlier and later stages of pregnancy merit further investigation.