Which cardiovascular parameter is decreased at term?

Which cardiovascular parameter is decreased at term?

• A. Central venous pressure (CVP)
• B. Pulmonary capillary wedge pressure
• C. Systemic vascular resistance
• D. Left ventricular end-systolic volume

Answer: (C)

During term pregnancy, the maternal vasculature undergoes dilation driven by placental factors and hormones such as progesterone and nitric oxide. This vasodilation lowers afterload, so systemic vascular resistance decreases. In response, the heart increases output to maintain perfusion, resulting in a high‑output, low‑resistance state characteristic of late pregnancy. Central venous pressure tends to be higher because blood volume expands, not lower. Pulmonary capillary wedge pressure, which reflects left atrial pressure, is typically normal or only mildly elevated due to increased preload. Left ventricular end-systolic volume can vary and isn’t the defining change seen at term. The most consistent and distinguishing change is the fall in systemic vascular resistance.

During term pregnancy, the maternal vasculature undergoes dilation driven by placental factors and hormones such as progesterone and nitric oxide. This vasodilation lowers afterload, so systemic vascular resistance decreases. In response, the heart increases output to maintain perfusion, resulting in a high‑output, low‑resistance state characteristic of late pregnancy.

Central venous pressure tends to be higher because blood volume expands, not lower. Pulmonary capillary wedge pressure, which reflects left atrial pressure, is typically normal or only mildly elevated due to increased preload. Left ventricular end-systolic volume can vary and isn’t the defining change seen at term. The most consistent and distinguishing change is the fall in systemic vascular resistance.