**Core Concept**
The **patent ductus arteriosus (PDA)** is a congenital heart defect characterized by the failure of the ductus arteriosus to close after birth, leading to an abnormal connection between the **aorta** and **pulmonary artery**. This condition can result in excessive blood flow to the lungs, potentially causing **pulmonary hypertension** and other complications. The management and clinical presentation of PDA depend on its size and the presence of symptoms.

**Why the Correct Answer is Right**
The correct answer is related to the frequency of **bacterial endocarditis** in patients with PDA. Bacterial endocarditis is indeed a complication of PDA, but it is more commonly associated with larger defects, not small ones. The mechanism involves the abnormal flow of blood through the PDA, which can lead to **turbulence** and increase the risk of **infective endocarditis**.

**Why Each Wrong Option is Incorrect**
**Option A:** is incorrect because spontaneous closure of the PDA does occur in some term infants, particularly within the first few days of life.
**Option B:** is incorrect because pulmonary hypertension can indeed develop as a consequence of a large, unrestrictive PDA, leading to increased pressure in the pulmonary arteries.
**Option D:** is incorrect because recurrent chest infections and congestive heart failure are potential complications of a significant, left-to-right shunting PDA.
**Option E:** is incorrect because the anatomic existence of a PDA, especially if it's large or symptomatic, is often an indication for surgical or transcatheter closure to prevent long-term complications.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that small PDAs are less likely to cause significant symptoms or complications in the short term but still pose a risk of bacterial endocarditis. Thus, even small PDAs may require closure, especially if they persist beyond early infancy.

**Correct Answer:** C. Bacterial endocarditis is more frequent with small PDA