Introduction

Have you ever wondered, how do I know if my child is growing properly? Is this behaviour normal? How can I track my child’s growth? At what age should my child start walking? How will I know if my child needs help? These questions might have crossed your mind at least once as you watched your babies grow. Such concerns are common and underscore the importance of monitoring your child’s growth, as recommended by paediatricians.

Intentionally monitoring child growth is advised by healthcare professionals to detect abnormalities early and take corrective actions. For instance, one major issue that can be detected through proper child growth monitoring is nutritional problems. According to the World Health Organization (WHO’s) 2022 report, globally, 149 million children under the age of 5 were estimated to be stunted (too short for their age), 45 million were wasted (too thin for their height), and 37 million were overweight or obese.

This problem can be detected early through regular weighing and comparing results with standard growth measures like weight-for-age. Moreover, beyond assessing your child’s nutritional needs and status, growth charts are used by government agencies to measure the well-being of the population, which aids in the formulation of health policies and planning interventions.

Monitoring your child’s growth and development involves not only frequent measurements but also maintaining growth charts, providing health advice to mothers, and ensuring follow-ups by healthcare professionals, among other tasks.¹

Do You Know?                                                                                     

Anthropometrics is a long fancy word that means ‘measurement of human beings’.

What should I measure for my child's growth?

Child growth and development go beyond monitoring physical parameters. Measuring child growth involves assessing parameters like height or length, weight, and head and chest circumference, and comparing them to growth standards.² Growth is usually measured in children up to five years old because their growth during the first five years will significantly impact their lifelong health.

The WHO recommends a standard growth chart for children under two years old, while parents are advised to switch to the CDC standard growth chart for children two years old and older. You can take these measurements at home or during routine appointments with your paediatrician. 

Here are the key measurements necessary to monitor growth:

Growth in infants and toddlers (under 2-years old)

• Length

Children in this category are measured in a supine position (lying down) on a measuring board with a sliding footpiece or on a supine stadiometer. This measurement involves positioning the child so that the crown of their head rests flat against the head plate, their knees are pressed down with legs stretched out, and their heels touch the footpiece. Infants typically increase in length by about 30% within five months and more than 50% within 12 months.³

• Weight

Weight is measured using various types of weighing scales (spring scales, hanging scales, digital scales, etc.). Infants typically lose their birth weight a few days after delivery but regain it within two weeks. During the first three months, they gain approximately 28g per day, followed by a total gain of 4kg between 3 and 12 months. By two years of age, they almost quadruple their birth weight.

• Head Circumference

Head circumference reflects brain size. It is measured by wrapping a flexible tape measure around the child’s head, from the forehead to the back (usually above the eyebrows). The size of the infant's brain is about 25% of the size of an adult brain, with an average head circumference of around 35cm. During the first eight months, growth is fast, with head circumference increasing by approximately 1cm per month. By 12 months, the brain reaches about 75% of its adult size.³

Growth in children (2-years and older)

• Height

For children, 2-years and older, their height is measured using a standing stadiometer. It can also be measured by having the child stand upright against a wall and measuring the distance from the top of their head to their heel. During the first year, children grow about 25cm, and by the age of five, they reach double their birth height. 

• Weight

It is measured in the same manner as for children under two years old. Children gain an average of 1.8kg to 2.7kg per year. Some studies suggest that rapid weight gain between six and 24 months is associated with an increased risk of childhood obesity. To identify obesity in children, a Body Mass Index (BMI)-for-age chart should be used and monitored over time.

• Body Mass Index (BMI) (optional)

The BMI is a parameter that is not directly measured but calculated using a BMI calculator. It is an index of weight and height obtained by dividing the child’s weight (in kg) by the square of their height (in meters). Children's BMI varies with age and sex, so the values are expressed relative to other children of the same age and sex. To calculate BMI for children under 20 years, the CDC BMI percentile calculator for children and teens is used. Child BMI categories and their corresponding sex- and age-specific BMI percentiles are presented in the following table:

Understanding growth charts and percentiles

As mentioned earlier, two widely accepted growth charts are used to monitor child growth: the WHO Growth Standard Chart and the CDC Growth Chart. However, growth charts may vary by country. In the UK, for instance, the UK-WHO Growth Chart is generally used for children under five years old.⁴

Measurements are most valuable when plotted on a growth chart and compared to standard measurements according to your child’s age. The purpose of the chart is to observe your child’s growth patterns and identify any abnormal increases or decreases in the standard growth parameters. To select an appropriate growth chart for your child, consider their age and sex, as boys and girls have different growth patterns.

When measuring the weight and length of children under two years, these WHO charts are recommended:

• WHO Weight-for-age 
• WHO Length-for-age 
• WHO Weight-for-length

A growth chart is easy to read when you understand its layout and how to interpret the data. The image below is a sample chart of the WHO Length-for-age chart for girls under two years old. The lines on a growth chart are called centile lines, and they are based on the measurements from many children. The curved lines represent percentiles that show the rank of your child’s measurements.

To find your child’s length percentile using the image below, you can follow these steps:

• On the vertical axis, locate your child’s length and use a straight-edge ruler to draw a horizontal line from that point
• On the horizontal axis, locate your child’s age and draw a vertical line until it meets with the horizontal line
• Make a small dot where the two lines intersect
• For example, if the dot is on the 85th percentile line, it means that 15 children would be taller than your child, and 84 would be shorter

It is important to note that your child’s health status cannot be determined from a single measurement. It is determined by the pattern formed over time.

Source: WHO

You can access Other Growth Charts Here:

UK-WHO Growth Chart

CDC Clinical Growth Charts

Problems that a growth chart can indicate

Remember, the aim of monitoring your child’s growth with a growth chart is to detect underlying health conditions early. When a child doesn’t develop and grow normally, it’s referred to as Failure To Thrive. An abnormal growth pattern may indicate several growth issues including:

• Obesity
• Malnutrition
• Endocrine (hormonal) diseases
• Genetic disorders
• Idiopathic conditions

Factors that influence your child’s growth

There are three categories of factors that can influence the growth of your child:⁵

• Nutritional factors
• Environmental factors 
• Genetics

FAQs

Can I measure my child’s growth at home?

Growth measurements are usually done during clinic appointments. However, they can be taken at home, provided they are done accurately and according to standard directions. It is recommended to share this data with your healthcare professional for proper plotting and interpretation of your child’s growth chart.

How do I know if my child has a growth delay?

A growth delay may indicated primarily if your child doesn’t grow more than two inches a year after their second birthday. However, if you are worried about your child’s growth, it's recommended to consult your doctor.

My baby was born preterm, does this growth chart still apply?

A preterm infant is born before 37 weeks gestation. For infants in this category, you can use the Fenton preterm growth chart from 22 weeks to 50 weeks. However, at 40 weeks, it should be used in conjunction with the term growth chart. When using the term growth chart (WHO growth chart), the infant’s age should be corrected to the age from the original due date.

How often should I measure my child?

Ideally, your child should be measured at the following intervals:⁶

• Within one to two weeks after birth
• At 1, 2, 4, 6, 9, 12, 18, and 24 months
• Annually between four to six years

My child has special needs, does this growth chart apply?

Yes, the CDC standard growth chart still applies to children with special needs, but it should be used with consideration of the influence of their health condition on their growth. However, disease-specific growth charts exist, such as the Growth Chart for Children with Down Syndrome.⁷

Summary

It is important to recognise that every child is unique, and growth patterns should not be compared with those of other children. If you have concerns about your child, it's best to consult your paediatrician directly. Growth monitoring goes beyond taking occasional measurements; it should be done diligently. Regular and proper measurements and monitoring can help identify disorders before symptoms appear, potentially allowing for early treatment that could save your child's life or improve the prognosis. Remember, a single growth chart cannot determine your child’s health status. What you need is a consistently observed and proportionate growth pattern over time to ensure the health of your child.