**Core Concept**
Corticosteroids are administered to pregnant women at risk of preterm delivery to accelerate fetal lung maturation and reduce the risk of respiratory distress syndrome (RDS). However, corticosteroids also have neuroprotective effects, reducing the risk of intraventricular hemorrhage (IVH) and periventricular leukomalacia (PVL) in preterm infants.

**Why the Correct Answer is Right**
Corticosteroids, specifically dexamethasone, have been shown to reduce the risk of IVH and PVL in preterm infants. This is thought to be due to the anti-inflammatory effects of corticosteroids, which reduce the permeability of the blood-brain barrier and decrease the release of pro-inflammatory cytokines. The resulting decrease in brain edema and oxidative stress helps to protect the developing brain from injury.

**Why Each Wrong Option is Incorrect**
**Option A:** Magnesium sulfate is used for fetal neuroprotection, but it is primarily used to prevent eclampsia and reduce the risk of cerebral palsy in preterm infants. It does not have the same neuroprotective effects as corticosteroids.
**Option B:** Indomethacin is a prostaglandin synthetase inhibitor used to promote fetal lung maturation and reduce the risk of RDS. However, it does not have significant neuroprotective effects.
**Option C:** Nifedipine is a calcium channel blocker used to prevent preterm labor. While it has some benefits for fetal lung maturation, it does not have significant neuroprotective effects.

**Clinical Pearl / High-Yield Fact**
When managing preterm labor, it's essential to remember that corticosteroids have both lung-maturing and neuroprotective effects, making them a crucial component of preterm delivery management.

**Correct Answer:** D. Dexamethasone.