**Core Concept**
Intrahepatic cholestasis of pregnancy (ICP) is a condition characterized by impaired bile flow, leading to elevated levels of bile acids in the blood. This condition poses a significant risk to both the mother and the fetus, necessitating prompt and effective treatment.

**Why the Correct Answer is Right**
The primary goal of treatment in ICP is to reduce bile acid levels and alleviate symptoms. Ursodeoxycholic acid (UDCA) is the first-line treatment for ICP, as it helps to reduce bile acid levels and improve liver function. UDCA works by inhibiting the hepatic uptake of bile acids and promoting their excretion into the bile. This results in a decrease in bile acid levels, which in turn reduces pruritus and other symptoms associated with ICP.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not address the underlying pathophysiology of ICP. While antihistamines and corticosteroids may provide some relief from pruritus, they do not directly affect bile acid levels or liver function.
**Option B:** This option is incorrect as it is not a standard treatment for ICP. While certain medications, such as phenobarbital, may be used in some cases, they are not the primary treatment for ICP.
**Option C:** This option is incorrect as it does not directly address the pathophysiology of ICP. While supportive care, such as hydration and bowel management, may be important in the management of ICP, they do not directly affect bile acid levels or liver function.

**Clinical Pearl / High-Yield Fact**
A key clinical pearl in the management of ICP is to monitor fetal well-being closely, as elevated bile acid levels can pose a risk to fetal health. Regular fetal monitoring and timely delivery are essential in preventing adverse outcomes.

**Correct Answer:** C. Ursodeoxycholic acid (UDCA)