**Core Concept**
Meconium peritonitis refers to the inflammation of the peritoneum, the thin layer of tissue that lines the abdominal cavity, caused by the leakage of meconium, the stool of a fetus, into the amniotic fluid. This condition is often associated with intestinal obstruction or perforation in the fetus.

**Why the Correct Answer is Right**
Meconium peritonitis occurs due to the leakage of meconium into the amniotic fluid, which can happen when there is an intestinal obstruction or perforation in the fetus. When the meconium enters the amniotic fluid, it can cause a severe inflammatory reaction in the peritoneum, leading to meconium peritonitis. The condition is often diagnosed prenatally or postnatally through imaging studies and can be associated with other complications, such as meconium aspiration syndrome.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the topic of meconium peritonitis.
**Option B:** This option is incorrect because meconium ileus is a different condition that involves the blockage of the small intestine by meconium, but it does not directly cause meconium peritonitis.
**Option C:** This option is incorrect because gastroschisis is a congenital defect of the abdominal wall that allows the intestines to protrude outside the abdomen, but it does not directly cause meconium peritonitis.

**Clinical Pearl / High-Yield Fact**
Meconium peritonitis is a serious condition that requires prompt recognition and management to prevent long-term complications, such as intestinal damage and bowel obstruction.

**Correct Answer:** D