How do you know when your baby is underweight?

What is the normal baby weight?

Since newborns, there are several indicators that are used as benchmarks in assessing whether your little one's growth and development is going well.

Apart from the height or length of the body and head circumference, there is still a baby's weight which is also an aspect of determining the baby's nutritional status.

One of the things that supports normal baby weight gain is nutritional intake obtained from solid food and daily drinks.

If the intake of these nutrients is able to meet the daily nutritional needs of the baby, the weight gain can certainly go well.

Conversely, if the intake of these nutrients tends to not meet the nutritional needs of your little one, this will automatically also affect his weight gain.

According to the Indonesian Pediatric Association (IDAI), the easiest way to find out a normal weight for a 12 month old baby is to compare it with the birth weight.

A 12-month-old baby should be three times his birth weight. However, you actually don't need to worry because each child's growth process is different.

As long as the baby's weight is in the normal range and is not less or more than that, it means that his development is good.

Indicators that are usually used to assess a baby's weight are body weight for age (BW / U) and body weight for length or height (BW / PB).

According to WHO and the Indonesian Ministry of Health, the baby's weight is said to be normal and not less or more when in the following ranges:

Baby boy

Based on the WHO table, the normal weight for male babies up to the age of 24 months is:

Age 0 months or newborn: 2.5-3.9 kilograms (kg)
Age 1 month: 3.4-5.1 kg
Age 2 months: 4.3-6.3 kg
Age 3 months: 5.0-7.2 kg
Age 4 months: 5.6-7.8 kg
Age 5 months: 6.0-8.4 kg
Age 6 months: 6.4-8.8 kg
Age 7 months: 6.7-9.2 kg
Age 8 months: 6.9-9.6 kg
9 months old: 7.1-9.9 kg
10 months old: 7.4-10.2 kg
Age 11 months: 7.6-10.5 kg
Age 12 months: 7.7-10.8 kg
Age 13 months: 7.9-11.0 kg
Age 14 months: 8.1-11.3 kg
Age 15 months: 8.3-11.5 kg
Age 16 months: 8.4-13.1 kg
Age 17 months: 8.6-12.0 kg
Age 18 months: 8.8-12.2 kg
19 months old: 8.9-12.5 kg
Age 20 months: 9.1-12.7 kg
Age 21 months: 9.2-12.9 kg
Age 22 months: 9.4-13.2 kg
23 months old: 9,5-13,4 kg
Age 24 months: 9.7-13.6 kg

The weight of baby boys who are in this range is considered normal or not less and more.

Baby girl

Based on the WHO table, the normal weight for female babies up to 24 months is:

Age 0 months or newborn: 2.4-3.7 kg
Age 1 month: 3.2-4.8 kg
Age 2 months: 3.9-5.8 kg
Age 3 months: 4.5-6.6 kg
Age 4 months: 5.0-7.3 kg
Age 5 months: 5.4-7.8 kg
Age 6 months: 5.7-8.2 kg
Age 7 months: 6.0-8.6 kg
Age 8 months: 6.3-9.0 kg
9 months: 6.5-9.3 kg
10 months old: 6.7-9.6 kg
Age 11 months: 6.9-9.9 kg
Age 12 months: 7.0-10.1 kg
Age 13 months: 7.2-10.4 kg
Age 14 months: 7.4-10.6 kg
Age 15 months: 7.6-10.9 kg
Age 16 months: 7.7-11.1 kg
Age 17 months: 7.9-11.4 kg
Age 18 months: 8.1-11.6 kg
19 months old: 8.2-11.8 kg
Age 20 months: 8.4-12.1 kg
Age 21 months: 8.6-12.3 kg
Age 22 months: 8.7-12.5 kg
23 months old: 8.9-12.8 kg
Age 24 months: 9.0-13.0 kg

Likewise for baby girls, if the measurement results of your little one's body weight are below this range, it means that they are less.

Meanwhile, if it is more than this range, the baby girl's weight is classified as overweight to be obese.

When is the baby underweight?

As previously explained, the easiest way to determine whether a baby is underweight, normal, or overweight is to compare it with birth weight.

If at the time your baby's weight has reached three times his body weight at birth, this means that the growth is normal.

But for more details, you can draw conclusions about the baby's weight category based on Permenkes No.2 of 2020.

Permenkes Number 2 Year 2020 categorizes baby weight based on age (BW / U) as follows:

Extremely underweight: less than -3 SD
Underweight: -3 SD to less than -2 SD
Normal weight: -2 SD to +1 SD
Risk of overweight: more than +1 SD

Permenkes Number 2 of 2020 categorizes baby weight based on body length (BW / PB) as follows:

Poor nutrition: less than -3 SD
Poor nutrition: -3 SD to less than -2 SD
Good nutrition: -2 SD to +1 SD
Risk of over nutrition: more than +1 SD to +2 SD
Over nutrition: more than +2 SD to +3 SD
Obesity: more than +3 SD

The unit of measurement is known as the standard deviation (SD). So, the baby's weight is said to be normal, aka not less and more when it is in the range -2 to +1 SD in the WHO table based on weight / age.

If they are under -2 SD, the baby is underweight or even very underweight. Meanwhile, if the baby is more than +1 SD the baby's weight is classified as more.

What causes the baby to be underweight?

A baby's weight that is classified as less and even lower than normal can be caused by several things. If this lack of weight is experienced by a newborn, it could be because he was born earlier than time (prematurely).

Babies are said to be premature when they are born at a gestational age that has not reached 37 weeks. Meanwhile, for babies who are several months old, underweight can be caused by insufficient nutritional intake.

In addition, certain medical conditions can also affect the baby's weight, making it less or less than normal.

Take for example babies born with congenital heart defects and celiac disease usually gain weight which tends to be slower than other babies.

When to see a doctor

IDAI explains that the first 1000 days of life, aka from the time the baby is in the womb until the age of two years, is the fastest development period.

That is why you may have heard that it is mandatory to fulfill your little one's nutritional intake properly during the 1000 days.

If it turns out that the baby's weight gain does not increase properly and even tends to continue to decline in the card to health (KMS), consult a doctor immediately.

The doctor will usually do a baby growth examination first to find out the cause and the appropriate treatment.