## **Core Concept**
Meconium is the first feces of a newborn, composed of materials ingested during the time spent in the uterus, including intestinal epithelial cells, lanugo, mucus, amniotic fluid, bile, and water. Its excretion is an important sign of the newborn's gastrointestinal maturity and function.

## **Why the Correct Answer is Right**
The correct answer indicates that meconium is typically excreted by a newborn until around the 3rd to 4th day of life. This timeframe is crucial because it signifies the transition from fetal to neonatal life and the establishment of normal bowel habits. The excretion of meconium usually starts within the first 24 hours of life and continues for several days.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option suggests a much earlier cessation of meconium excretion, which does not align with the typical clinical observation that meconium passage continues for several days.
- **Option B:** This option implies a very short duration for meconium excretion, which underestimates the usual timeframe.
- **Option D:** This option suggests a longer duration than what is typically observed for the excretion of meconium.

## **Clinical Pearl / High-Yield Fact**
A significant clinical pearl is that the presence of meconium within the first 24 hours of life is an indicator of fetal well-being, particularly in the context of gestational age and potential fetal distress. Delayed passage of meconium (beyond 48 hours) can indicate issues such as intestinal obstruction or immaturity of the gut.

## **Correct Answer:** . 4th day.