What is the weight range for premature infants?

Premature infants are classified into various groups based on their birth weight.

- Extremely low birth weight: less than 1000 grams or 2 pounds, 3 ounces

- Very low birth weight: 1000 to 1500 grams or 2 pounds, 3 ounces to 3 pounds, 5 ounces

- Low birth weight: 1500 to 2500 grams or 3 pounds, 4 ounces to 5 pounds, 8 ounces.