**Core Concept**
Pregnancy with heart disease is a complex clinical scenario where the cardiovascular system undergoes significant changes. The body's increased demand for oxygen and nutrients, coupled with the heart's increased workload, can exacerbate underlying cardiac conditions.

**Why the Correct Answer is Right**
In pregnancy with heart disease, the **decreased systemic vascular resistance** is a characteristic feature, as the body adapts to the increased cardiac output. This decrease in vascular resistance is not seen in normal pregnancy, where systemic vascular resistance actually **increases**. The mechanisms behind this adaptation involve the **relaxation of vascular smooth muscle** and the **decrease in plasma volume**, which are mediated by various hormonal changes, including the increase in progesterone levels.

**Why Each Wrong Option is Incorrect**
**Option A:** Increased systemic vascular resistance - This is actually seen in normal pregnancy, not in pregnancy with heart disease.
**Option B:** Increased cardiac output - While cardiac output does increase in normal pregnancy, the proportionate increase in heart rate and stroke volume is more pronounced in pregnancy with heart disease.
**Option C:** Decreased left ventricular contractility - This is not a characteristic feature of pregnancy with heart disease; in fact, left ventricular contractility may actually **increase** in response to the increased demand for oxygen and nutrients.

**Clinical Pearl / High-Yield Fact**
Pregnancy with heart disease requires close monitoring and management to prevent complications. The decreased systemic vascular resistance in these patients can lead to **decompensation** of the underlying cardiac condition, highlighting the need for careful monitoring and management.

**Correct Answer: A. Increased systemic vascular resistance**