What is pediatric somatometry? How do I know if my baby is the right size and weight? We will explain everything to you.
Somatometry is a term that groups together all the techniques used to measure the human body. Pediatric somatometry thus makes it possible to observe the growth of a newborn baby, thanks to different measurements: height, weight and cranial and thoracic perimeter.
For infants, somatometry is used to detect measurements that are not consistent with normal body measurements. These calculations are done for the first time right after childbirth, when the baby is just born.
Have you ever wondered how children's measurements are calculated and what values are considered normal? We get back to you!
See also: These tips will make life easier for pregnant women
How are baby's measurements calculated?
When a baby is born, medical staff first clean the infant and then take their measurements. At that point, they calculate:
- The weight : by placing the child on the baby scale and placing a cloth or towel underneath to prevent loss of body heat.
- Size : which is taken in a horizontal position on the neonatometer (tool used to measure the length of the baby).
- Head circumference or cranial perimeter : This is the maximum width of the head, a measurement taken with a flexible tape measure.
- The thoracic perimeter : it is a measurement which follows the circumference of the thorax.
In addition, heart rate (120 – 160 beats per minute), respiratory rate (40 – 60 breaths per minute) and temperature (approximately 37ºC) are also evaluated.
Measurements of a newborn
First of all, know that every baby is different and that their weight and measurements can depend on many factors, such as genetic, fetal, maternal or demographic causes, for example.
Regarding weight, one must take into account the so-called physiological weight loss of the child, which occurs during the first days of a newborn's life. During this completely natural phase, it eliminates liquids through urine and sweat, as well as its meconium (excrement accumulated in the intestines of the fetus, constituting the first stools of the infant). He can lose up to 10% of his total weight.
However, some estimated measures are established for newborns. They serve as a benchmark for medical staff to assess the infant's state of health and development.
- The weight generally varies between 2.5 and 4 kilos. A baby of small weight (less than 2.5 kilograms) should be placed under supervision. A baby over 4 kilograms is considered to be overweight. We then speak of macrosomia.
- The average height is usually around 50 centimeters.
- The average head circumference of the newborn is about 34 centimeters.
- The thoracic perimeter is usually two centimeters less than the cranial perimeter.
Percentile and growth charts
As we mentioned, these values are approximate. To determine if a baby has measurements considered "normal", health professionals use growth charts created by the WHO. They allow to know the percentile of the baby according to the height or the weight associated with each age group, height, sex or length. Tables can tell us what percentile range our infant is in and help us track its development and growth. The pediatrician will be responsible for this follow-up.
You can consult the different growth charts for children on the World Health Organization website, as well as in our article dedicated to the ideal weight of a child according to his age and height.
Take baby's measurements at home
At home, using the different WHO growth charts, you can take your baby's measurements and assess his growth. Of course, these measurements may not be exact and it is those communicated by the pediatrician that you should take into account.
In order to weigh a baby, be sure to take off his shoes and clothes. For a child under two years of age, it is necessary to measure his height when lying down. If you are using a measuring board, lay it flat before placing your infant on their back. His head should be placed so that the baby's line of sight is perpendicular to the board. Be sure to gently hold their feet before bringing the sliding part of the board closer to the soles of the child's feet. Be careful, it is important to be accompanied when you take this measure, especially to ensure the safety of the baby. Never leave him alone on the board and make sure you always have a hand on him to prevent him from falling.
Electronic baby scales to help you measure the child's weight
Mattress gauges to measure your infant
Wall measuring boards to measure your child