When you book a visit to the pediatrician, the first thing the doctor does is calculate the percentiles for boys. But what are they and how are they calculated?
Growth is an important indicator of a child’s health. Graphical percentiles allow healthcare professionals to track and measure a child’s height and weight from birth to young adulthood. There are charts from birth up to age 5 and another chart for the older ones. The tables calculate percentiles are graphs that bring together the percentage values of weight and height of children (and for the smallest also head circumference), divided by sex and age.
In this article
Calculating percentiles for boys: what they are
Defined by the World Health Organization, growth curves refer to ideal growth measures for children in different parts of the world. They are ideal sizes for babies in ideal growing conditions, breastfed until about the 6th month and then weaned. During checkups at the pediatrician, the doctor assesses the general health of the child and discusses the progress of neurological, motor and cognitive development, weight and height with the parents. During the visit, he also receives information on the child’s habits, sleep and nutrition. This is useful and necessary information for the development and growth of the child.
Why growth curves matter
Both the growth curves from 0 to 24 months and those from 2 years to 18 years are important, explains Dr. Fabrizio Ciralli of Humanitas Pius X, because growth changes can occur at any time, even as adolescents. In the first two years of life, for example, a reduction in the growth percentile of a breast-fed baby should not scare but it is important to contact the pediatrician because it could be due to a reduction in the production of breast milk, food intolerances during weaning, or other causes, even transitory . On the other hand, a growth slowdown in an adolescent can depend on the genetic target.
Generally speaking, growing children are considered normal between the 25th and 75th percentile, but it doesn’t mean that those that grow on upper or lower curves have something wrong. In any case, the pediatrician will make the correct assessments on the weight and growth of the child and monitor them, month after month.
Percentile calculation for boys: how they work
The typical growth percentile calculation for children includes the following parameters:
- Weight (without clothes)
- Height (As long as the baby cannot stand, it will be measured from head to heel while lying down)
- Head circumference (a tape measure is used around the largest area of the head)
A percentile of 50 represents average weight or height. A value below the 50th percentile means that a child weighs less than the average. A value above the 50th percentile means that a child is above average. A optimal growth rate it must appear as a curve that is as comparable as possible with one of the percentile lines on the graph.
Are the growth curves the same for males and females?
Obviously not, because although the greatest differences are found starting from puberty, growth is in any case, generally, different starting from birth, in fact boys are on average more “robust” than girls of the same age and ethnicity.
Head circumference (to be evaluated at least up to 2 years)
UP TO 12 MONTHS – The head circumference (about 33-36 cm at birth) increases by about 12 cm in the first year:
- increases by 5 cm in the first 3 months
- increases by 3 cm between 3 and 6 months
- increases by 2 cm between 7 and 9 months
- increases by 2 cm between 9 and 12 months.
BETWEEN 2 AND 3 YEARS – The head circumference increases by about 5 cm
AFTER 3 YEARS – The head circumference can increase a little more, by about 1 cm / year, for a few years
UP TO 12 MONTHS:
- during the first 2-3 months of life the baby grows between 150 and 250g per week
- the newborn usually doubles in weight around 5 months
- newborns typically triple their weight at 12 months
BETWEEN 12 AND 24 MONTHS – Weight increases by about 3.5 kg (i.e. quadruple compared to birth)
BETWEEN 2 AND 4 YEARS – The weight increases by about 2-4 kg / year
BETWEEN 5 YEARS AND ADVERTISING – Weight increases by about 2.5 kg / year
Length / Height
UP TO 12 MONTHS – during the first year the length increases by about half of the birth value (about 2 cm per month)
- in the first 6 months the baby grows by about 2.5 cm / month
- between 6 and 9 months the baby grows about 4 cm
- between 9 and 12 months the baby grows by another 4-5 cm
BETWEEN 12 AND 24 MONTHS – Height increases by about 12cm (about 1cm / month)
BETWEEN 2 AND 4 YEARS – The height increases by about 6-8 cm / year
BETWEEN 5 YEARS AND PUBERTY – The height increases by about 5 cm / yy
Article sources Humanitas San Pio X