Which is the expected monthly increase in head circumference for 4 to 6 months of age?

After birth, in the first three months, the child grows the fastest, and then intensive growth continues, but with a slight slowdown. In this period, nutrition and still insufficiently defined genetic factors have a key influence on the growth rate, along with the appropriate support from the immediate environment. Childhood illnesses can be disruptive, but with your adequate support, they usually have a temporary effect.

• Your child's growth is assessed by measuring growth parameters: body weight, body length (length is measured when the baby is lying down up to 2 years of age) and head circumference, and then comparing them with growth standards issued by the World Health Organization (WHO). For day-to-day use, these standards have been translated into growth charts which are created differently for boys and for girls.
• At each routine health check-up (the number of visits varies across countries), your child will be measured, and the obtained values will be entered into growth charts, thus monitoring if your child is growing well and whether s/he is on track.  

At birth:

• Average values of body weight and body length at birth, are slightly higher in boys (about 3600 g and 51.5 cm) compared to girls (about 3500 g and 50.5 cm), which clearly reflects the influence of genetic factors on growth. Average head circumference is about 35cm.

First month:

• Do not be surprised if your child loses up to 10% of her body weight in the first days after birth. This is expected, the loss is temporary and will be compensated with proper care and nutrition, preferably with breast milk, no later than by the end of the second week of life.
• In the coming days, the child is expected to start gaining weight, on average 20 to 30 g a day.
• The first month is the month when the is child getting used to the living conditions in the external environment and there are great variations in growth. That is why it may happen that your child gains only 400 grams, or if he is born big, often asks to be breastfed and sleeps well, he may gain 1000 grams and more. During this time, he grows 4.5 to 5 cm on average.
• The growth of the head is especially monitored because it is conditioned by the speed of brain growth. The brain is being filled with a lot of information from the environment and is growing at a fantastic speed, so during this month the head circumference can increase by about 2.5 cm.

First three months:

• Your baby will continue to grow at about the same speed as during the first few weeks of life. During these months, she is expected to gain 700 to 900 grams, to grow 2.5 to 4 cm and 1.2 cm in head circumference per month. The figures given are only average values and therefore mild deviations are possible for typical growth and your child`s progress will be assessed based on the overall picture.

6 months:

• From the fourth to the seventh month, the child will continue to gain about 450 to 550 g per month. During this time, he will grow about 6 cm and the head circumference will increase by about 2.5 cm.
• In the period from the 4th to the 6th month, most children double their birth bodyweight. For premature babies, this can happen during 3-4 months of age.

Each child's growth is unique, and if the child has optimal nutrition and a nurturing environment, it generally follows the growth pattern established in the first months of life, while regular measurements and keeping growth charts help us to monitor it properly.

Child Age

1st month

2nd month

3-4 months

5-6 months

References and comments

WHO child growth standards and the identification of severe acute malnutrition in infants and children. A Joint Statement by the World Health Organisation and the United Nations Children s Fund.