**Core Concept**
Infants of diabetic mothers (IDMs) are at an increased risk of hypoglycemia due to excessive insulin production during fetal life. This excess insulin can lead to hypoglycemia after birth, particularly in the first few days.

**Why the Correct Answer is Right**
The correct answer is due to the pathophysiology of IDM. In diabetic mothers, high glucose levels stimulate the fetal pancreas to produce excess insulin. This results in fetal hyperinsulinism, which can lead to hypoglycemia after birth when the glucose supply from the mother is interrupted. The hypoglycemia can cause seizures in the newborn.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not relate to the pathophysiology of IDM. Hypocalcemia can cause seizures but is not the most probable cause in this scenario.

**Option B:** This option is incorrect as it is not directly related to the risk factors associated with IDM. Congenital infections or metabolic disorders can cause seizures, but they are not the most probable cause in this scenario.

**Option C:** This option is incorrect as it is not a direct consequence of IDM. Hypertension in the mother can cause various fetal complications, but it is not the most probable cause of seizures in this scenario.

**Option D:** This option is incorrect as it does not directly relate to the pathophysiology of IDM. Congenital heart disease can cause various complications, but it is not the most probable cause of seizures in this scenario.

**Clinical Pearl / High-Yield Fact**
Infants of diabetic mothers are at increased risk of hypoglycemia due to fetal hyperinsulinism, and it is essential to monitor their glucose levels closely in the first few days after birth.

**Correct Answer:** D.