What is the best way to plot a growth chart for a pediatric patient, using either clinical measurements or ultrasound?

Growth Chart Plotting: Use Clinical Measurements, Not Ultrasound

Growth charts should always be plotted using postnatal clinical measurements (weight, length/height, head circumference), not prenatal ultrasound measurements. Growth charts are designed as clinical tools for monitoring postnatal growth patterns and identifying children whose growth might indicate adverse health conditions 1.

Which Growth Charts to Use

The choice of growth chart depends on the child's age:

• For children under 24 months: Use WHO growth charts, which reflect optimal growth patterns among predominantly breastfed infants 1
• For children 24-59 months and older: Use CDC growth charts, which extend continuously through age 19 years 1

This age-based transition is recommended because WHO charts are based on international optimally nourished breastfed infants, while CDC methods align better with growth patterns after age 24 months 1.

Clinical Measurements Required

Plot the following parameters using accurate clinical measurements:

• Weight: Measured at every visit and plotted on weight-for-age curves 1, 2
• Length (under 24 months) or Height (24+ months): Measured using appropriate technique (recumbent length vs standing height) 1, 2
• Head circumference: Particularly important in infants and young children under 24 months 3
• Body Mass Index (BMI): Can be calculated and plotted for children over 24 months 2

Why Not Ultrasound Measurements

Prenatal ultrasound measurements serve a different purpose—assessing fetal growth in utero. These measurements:

• Use different reference standards (fetal growth curves, not postnatal growth charts) 4
• Cannot be plotted on standard pediatric growth charts designed for postnatal measurements 1
• Do not predict postnatal growth trajectory with sufficient accuracy for clinical monitoring 4

Critical Plotting Principles

Serial measurements over time are more informative than single data points 2, 5. When plotting:

• Ensure accurate age calculation, especially for premature infants who require gestational age correction until 24 months 6
• Plot measurements at consistent intervals: monthly for infants under 12 months, every 3-6 months for older children 2
• Look for growth velocity and trajectory, not just percentile position 2, 5
• Use the 2.3rd percentile (labeled as 2nd percentile) and 97.7th percentile (labeled as 98th percentile) as thresholds for identifying potential adverse health conditions 1

Common Pitfalls to Avoid

• Plotting errors: Studies show 28.5% of points are plotted incorrectly, most commonly due to age calculation errors on the horizontal axis 6
• Failure to adjust for prematurity: Premature infants require gestational age correction when plotting on growth charts 6
• Mixing measurement types: Do not switch between recumbent length and standing height without accounting for the difference (approximately 0.8 cm) 2
• Single measurement interpretation: A child consistently tracking at the 3rd percentile may be normal, while a child crossing downward through percentile lines indicates growth faltering requiring evaluation 2, 5

Electronic vs Paper Charts

Electronic health record systems with integrated growth charts offer advantages over paper charts 7, 8:

• Automatic plotting reduces calculation and transcription errors 7, 8
• Real-time visualization of growth trajectory during clinical encounters 8
• Ability to perform calculations and adapt to patient characteristics automatically 8

However, clinicians must still verify accuracy of entered measurements and understand proper interpretation regardless of the medium used 6.