## **Core Concept**
Extremely low birth weight (ELBW) is a classification used for newborns who have a very low birth weight. Birth weight is a critical indicator of a newborn's health and development. The classification of birth weight helps in assessing the risk and guiding the management of newborns.

## **Why the Correct Answer is Right**
The correct answer defines extremely low birth weight as less than 1000 grams. This classification is significant because infants with ELBW are at a higher risk of experiencing complications and require specialized care. The World Health Organization (WHO) provides classifications for birth weight, and ELBW is specifically defined as a birth weight below 1000 grams.

## **Why Each Wrong Option is Incorrect**
- **Option A:** 1500 grams - This is actually the definition for very low birth weight (VLBW), not extremely low birth weight.
- **Option B:** 2000 grams - This is not a standard cutoff for ELBW or VLBW; it's higher than both.
- **Option D:** 2500 grams - This is the cutoff for low birth weight, not ELBW or VLBW.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the classification of birth weight is crucial for predicting neonatal outcomes. ELBW infants (<1000 grams) have the highest risk of mortality and morbidity among all birth weight categories. Understanding these definitions helps in assessing the level of care required for newborns. ## **Correct Answer:** . 1000 gm.