Birth to 24 Months: Infant Height and Weight Overview

Like many other parents, you can’t escape the worry about whether your baby is developing healthily. Generally, the growth process of infants is quite continuous and predictable. In addition to taking your child to a healthcare facility, parents can refer to the standard height and weight chart for infants provided by the WHO.

Principles of Measuring Height and Weight for Infants

The principle of measuring height and weight for infants is a crucial one that parents should understand: it is best to measure when the baby is lying down. This involves measuring the distance from the top of the head to the heel, and it should be done with the help of both parents.

The steps for measuring an infant’s height are as follows:

  1. Lay the baby flat on the ground, a table, or a long bench (as long as it is flat). Remove any bulky clothing, leaving only the diaper on.
  2. Ensure that the baby’s head is firmly against a flat surface like the headboard or a wall.
  3. For accurate measurement, both parents should participate. The father should hold the baby’s legs straight, and the mother should gently hold the baby’s head on both sides.
  4. Place the measuring tape flat next to the baby.
  5. Measure the distance from the top of the head to the heel.
  6. Record the exact height, rounded to the nearest 0.04 inch (0.1 cm).
Simulating Accurate Infant Height Measurement

Simulating Accurate Infant Height Measurement.

Parents should also be aware that the height measurement while lying down and while standing may differ by 0.985 inch (2.5 cm).

Since infants are too small and cannot stand on a scale, parents can weigh their baby at home by using the following method: First, weigh yourself, then weigh yourself again while holding the baby. The baby’s weight is the difference between the two measurements. Repeat this process at least twice to obtain the most accurate result.

Standard Height and Weight Chart for Newborns by Month

The World Health Organization (WHO) has provided a month-by-month standard height and weight chart for newborns to help parents conveniently monitor their child’s healthy development.

Standard Height and Weight Chart for Newborn Girls

Below is the standard height and weight chart for newborn girls. In this chart, the figures in the “Average” columns for height and weight represent the standard height and weight that newborn girls are expected to achieve at that particular time.

Time PeriodHeight (inches) -2SDHeight (inches) AverageHeight (inches) +2SDWeight (pounds) -2SDWeight (pounds) MeanWeight (pounds) +2SD
Newborn17.8719.3320.835.297.059.26
1 month19.6121.1422.687.059.2612.13
2 months20.8722.4824.058.6011.2414.55
3 months21.8923.5425.209.9212.7616.53
4 months22.7624.4526.1411.0214.1118.08
5 months23.4625.2027.0012.1315.2119.40
6 months24.0925.8727.6713.2316.0720.50
7 months24.6826.6528.3514.1116.7621.61
8 months25.2027.0529.1314.9917.4222.49
9 months25.6727.6029.5315.4318.0823.15
10 months26.1828.1530.0815.8718.7423.97
11 months26.6928.6330.6316.3119.1324.69
12 months27.1229.1331.1816.5319.6925.79
15 months28.3530.5132.6817.6421.1628.99
18 months29.4931.7534.0518.2922.4930.91
21 months30.5132.9535.3518.9623.9732.63
24 months31.5033.9937.0919.8425.3534.39

Standard Height and Weight Chart for Newborn Boys

Similarly, parents can rely on the ‘Mean’ column in the standard height and weight chart for newborn boys to monitor their child’s healthy development.

Time PeriodHeight (inches) -2SDHeight (inches) AverageHeight (inches) +2SDWeight (pounds) -2SDWeight (pounds) AverageWeight (pounds) +2SD
Newborn17.8719.3320.835.297.059.26
1 month19.6121.1422.687.059.2612.13
2 months20.8722.4824.058.6011.2414.55
3 months21.8923.5425.209.9212.7616.53
4 months22.7624.4526.1411.0214.1118.08
5 months23.4625.2027.0012.1315.2119.40
6 months24.0925.8727.6713.2316.0720.50
7 months24.6826.6528.3514.1116.7621.61
8 months25.2027.0529.1314.9917.4222.49
9 months25.6727.6029.5315.4318.0823.15
10 months26.1828.1530.0815.8718.7423.97
11 months26.6928.6330.6316.3119.1324.69
12 months27.1229.1331.1816.5319.6925.79
15 months28.3530.5132.6817.6421.1628.99
18 months29.4931.7534.0518.2922.4930.91
21 months30.5132.9535.3518.9623.9732.63
24 months31.5033.9937.0919.8425.3534.39

The important thing to note is that if a baby deviates slightly from this standard but still falls within the range of underweight (-2SD) or overweight (+2SD), parents can rest assured.

Important Considerations for 2SD Scores in Measuring Infant Height and Weight

When looking at the standard height and weight chart for infants, parents may notice two columns: -2SD and +2SD. So, what does the 2SD score mean, and how should these scores be interpreted?

SD stands for Standard Deviation, which represents the degree of deviation from the mean. In addition to the mean (TB), there are other standard deviation levels ranging from 1 to 3, with the symbols (-) and (+) indicating below or above.

Interpreting the 2SD Weight Score

The 2SD weight score, as defined by the WHO, is divided into -2SD, referred to as the lower limit, and +2SD, referred to as the upper limit. If a child’s measured weight falls below -2SD, it means the child weighs only about 80% of the standard, indicating a risk of malnutrition or underweight. Conversely, if the measured weight is above +2SD, the child is at risk of overweight or obesity.

Interpreting the 2SD Height Score

Similar to weight, the 2SD height score is also divided into -2SD, the lower limit, and +2SD, the upper limit. A height measurement below -2SD indicates that the child is at risk of stunting or being underdeveloped in height. Conversely, a height measurement above +2SD means the child’s height is above the normal range.

Height and weight are two indicators of a healthy infant’s development. By understanding a child’s 2SD scores, parents can determine whether their child is developing healthily or at risk of health issues and take timely corrective actions.

Healthy development in the early years is a stepping stone for the next stages.

Healthy development in the early years is a stepping stone for the next stages.

Infant Height and Weight Percentiles by Age

The process of growth and body development is robust during the infant stage. Tracking infant height and weight percentiles by age can often surprise many parents.

Newborns

Newborns typically measure about 50cm in length and weigh around 3.3kg (7.3 pounds). Additionally, the head circumference of a newborn is closely monitored, with baby girls averaging around 33.8cm (13.3 inch) and baby boys around 34.3cm (13.5 inch).

Birth to 4 Days Old

In reality, most newborns will leave the hospital weighing slightly less than their birth weight. Approximately 5-10% of their weight will decrease during the first week due to fluid loss and bowel movements.

5 Days to 3 Months Old

Infants can gain an average of 15-28 grams (0.529-0.987 Ounce) per day during this period. Within just two weeks, an infant’s weight will return to their birth weight. Both weight and height will continue to increase significantly. By the age of 3 months, infants will have gained over 30% in weight and 20% in body length.

3 to 6 Months Old

Between 3 to 6 months of age, infants can gain around 225 grams (0.5 pound) every two weeks. With this rate of growth, infants will double their birth weight by the time they reach 6 months. Along with physical growth, motor skills and overall physical abilities of the infant also undergo significant changes.

From the sixth month onward, children will gradually undergo physical and motor skill changes.

From the sixth month onward, children will gradually undergo physical and motor skill changes.

7 to 12 Months Old

From 7 to 12 months of age, an infant’s body weight will continue to increase by 500 grams each month. This weight gain often leads to tripling the birth weight by the age of 1. Infants typically grow an additional 25cm (9.84 inch) in their first year, with an overall height reaching approximately 72-76cm (28.34-29.9 inch) by their first birthday.

Factors Affecting Infant Height and Weight

According to scientists, the development of infant height and weight is influenced by various factors, including genetic inheritance, nutrition, breastfeeding, and supplementation, as well as exposure to sunlight. It is important to regularly monitor the height and weight chart of infants to adjust their body indices.

Genetic Factors

Genetic factors have a significant impact on a child’s overall development. Height is primarily controlled by a combination of genetic variations along with environmental factors, such as nutrition.

More than 700 gene variants have been identified to influence height. Some of these variants are involved in genes that directly or indirectly affect cartilage, thereby contributing to bone elongation and helping children grow taller. However, genetic inheritance accounts for only about 23% of height variability.

In-Utero Nutrition

Physical development, especially a newborn’s weight, is heavily influenced by the nutrition they receive while in their mother’s womb. A prime example is the impact of malnutrition leading to delayed growth in infants.

Health experts have determined that malnutrition not only reduces bone density and oral health but also has negative effects on developmental abilities during adolescence and pre-adolescence. Therefore, nutrition plays a crucial role in a child’s overall development.

Breastfeeding and Nutritional Supplements

Breast milk protects an infant’s delicate digestive system from potential infections. If a child is breastfed within the first hour after birth, it can contribute to reducing the mortality rate from diseases such as diarrhea and infections. Breast milk also provides abundant nutrition for the child. From infancy to the age of one, breast milk can meet half of a child’s energy requirements.

During infancy, a child’s body is still fragile, and they need time to adapt to their environment. Parents should only provide nutritional supplements to their child when it is genuinely necessary and under the guidance of a medical professional.

Sunlight Exposure

The Indonesian Pediatric Society (IDAI) recommends the best time for sunlight exposure to be between 6:00 AM and 7:30 AM when the sunlight is not too harsh. If circumstances and conditions do not permit, do not force a baby to be exposed to sunlight. Ensure that the baby’s eyes are not directly exposed to sunlight during sunbathing. Parents can use thin fabric to cover the baby’s eyes or position the baby’s head away from direct sunlight.

The ideal time for sunbathing newborns is early morning.

The ideal time for sunbathing newborns is early morning.

Read more: Exercises for Height Increase in Children

What Mothers Should Keep in Mind for Comprehensive Infant Development

To ensure comprehensive development in infants, parents should consider the following:

  • Provide infants with a healthy and timely source of nutrition.
  • Prioritize breastfeeding over formula feeding.
  • When the child reaches 6 months of age, introduce diversified solid foods such as vegetables, meat, fish, eggs, fruits, etc., in combination with breastfeeding.
  • Regularly monitor the child’s health to take timely action when factors affecting their development are identified.

The first three years of life are a critical period when a child maximizes their genetic potential, laying the foundation for exceptional growth in subsequent stages. Regularly monitoring a child’s health, as well as their height and weight, is essential and should not be underestimated.

Through this article, we hope that parents can refer to the standard height and weight chart for infants to adjust their nutrition and promote appropriate height and weight development for their little ones.

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