The length of a baby will be measured at birth and during every doctor’s visit to determine their health. Our data shows the global averages based on Your Child’s sex.
Why does birth length matter?
During their first year, babies tend to have a predictable growth rate. Babies who grow unusually slowly during the first year may have a health or developmental issue. A baby’s growth pattern is usually relative to their length at birth, so a doctor will measure a newborn’s birth length to predict their growth pattern during the first year. Contrary to popular belief, birth length is not an indicator of how tall a baby will be in the future, but it will give the doctor an idea of the genetic and environmental influences inside the womb.
How do I measure a baby’s length?
Most hospitals measure a baby using a horizontal length board. To measure a baby at home, lay them onto a firm surface and use a measuring tape to measure Your Child from the top of the head to the heel of one foot.
What is the average length of a full-term newborn?
On average, a baby will be around 45.7 to 60 cm, depending on their ethnicity and mother’s height. By the first month, the baby must have grown by approximately 4 cm. On average, babies will grow at the rate of 3 cm per month until the 5th month, when the average growth rate reduces to 2 cm per month. After month 8, it is not unusual for babies to grow just 1-1.5 cm longer by the end of the month. The firstborn is usually smaller than their later siblings. Boys are, on average, taller than girls.
What to do if my child’s birth length is shorter or longer than the average?
If a baby’s length and weight are unusually small, they may have a health problem that needs to be examined. However, length alone doesn’t predict a baby’s health, and most smaller babies end up growing to a similar height as their parents. However, your baby’s length will be recorded at every doctor’s visit, and their growth patterns examined. If their growth rate is unusually faster or slower than normal, the doctor may want to check for any underlying problem.
Our data and information are based on information from the World Health Organisation and based on global averages of full-term infants who are born at 37 weeks or later.
The graphs we show are based on a child’s sex. If the sex was set as “unknown”, we use growth charts of female babies.
Premature babies are monitored via a different growth chart specifically designed for babies born during the gestational ages of 25-36 weeks. See the sources below for more information.
Dr. Piyawut Kreetapirom, MD. (30 March 2021)