A baby whose birth weight is 3 kg, what will be his expected weight at the age of 4 years?

Chitranjjan National Cancer Institute Kolkata - 2021

Child Health Nursing (Pediatrics)

Medium

Appeared in: Chitranjjan National Cancer Institute Kolkata - 2021

Explanation

The most common formula to estimate a child's weight between 1 and 6 years is: Weight (kg) = (Age in years × 2) + 8.
Applying this formula for a 4-year-old child: (4 × 2) + 8 = 8 + 8 = 16 kg.
Alternatively, weight milestones can be used. A child's birth weight typically quadruples by 2 years (3 kg × 4 = 12 kg).
From age 2 to 7, a child gains approximately 2 kg per year.
Therefore, at 4 years, the weight would be the weight at 2 years (12 kg) plus the gain for two more years (2 kg + 2 kg), totaling 16 kg.

Option A: A weight of 6 kg is significantly below the expected weight for a 4-year-old and would indicate severe underweight or failure to thrive.
Option B: A weight of 12 kg is the expected weight for a 2-year-old, not a 4-year-old.
Option C: A weight of 14 kg is closer, but still below the expected average for a 4-year-old.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pediatric growth and development, specifically calculating expected weight for age as background academic context rather than a clinical decision trigger.
Monitoring a child's weight is a fundamental part of pediatric health assessments. It helps in tracking growth patterns and identifying potential nutritional deficiencies, developmental delays, or other health issues early on.
Nurses use these formulas for quick bedside assessments and to provide anticipatory guidance to parents about their child's growth and nutritional needs.
What if? If the child was 4 years old but weighed only 12 kg, this would be a significant red flag. The nurse should perform a detailed nutritional assessment, inquire about feeding habits and recent illnesses, and report the finding of 'underweight' or 'failure to thrive' to the pediatrician for further investigation.

How to Approach the Question

First, identify the key information given in the question: the child's age (4 years) and the context (expected weight).
Recall the standard formulas for estimating a child's weight. For the 1-6 year age group, the most common formula is (Age in years × 2) + 8.
Substitute the child's age into the formula: (4 × 2) + 8.
Perform the calculation: 8 + 8 = 16.
Compare your calculated result (16 kg) with the given options.
Select the option that matches your result. You can also cross-verify using the weight milestone method (quadruple birth weight by 2 years, then add 2 kg per year).

Concept Tested & Keywords

Concept Tested: Pediatric growth and development, specifically calculating expected weight for age.
Stem keywords: birth weight, 3 kg, expected weight, 4 years
Lead-in keywords: what will be

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