Most newborn babies follow a predictable level of growth during their first year. People can track the length of their baby using average growth charts.
The average length of a full-term newborn baby is
Male babies are slightly longer than female babies. Doctors measure a baby’s length from the top of their head to the heel of their foot.
This article looks at the average baby length, month-by-month, for the first year of life. We also discuss what it means when a baby is shorter or longer than average and when to speak with a doctor.
The World Health Organization (WHO) publishes standard infant growth charts according to the expected growth of children in
It is important to note that most people use the terms “length” and “height” interchangeably. However, until the age of 2 years, most doctors will measure babies’ lengths lying down. In measurement terms, experts call this recumbent length. This is different from height, which doctors will measure after the
In the first year of their lives, babies typically grow in length by 50%. According to the WHO’s growth charts, the average lengths for
|Age||Male baby||Female baby|
|Birth||19.69 in (50 cm)||19.29 in (49 cm)|
|1 month||21.65 in (55 cm)||21.26 in (54 cm)|
|2 months||23.03 in (58.5 cm)||22.44 in (57 cm)|
|3 months||24.21 in (61.5 cm)||23.62 in (60 cm)|
|4 months||25.20 in (64 cm)||24.41 in (62 cm)|
|5 months||25.98 in (66 cm)||25.20 in (64 cm)|
|6 months||26.77 in (68 cm)||25.48 in (66 cm)|
|7 months||27.17 in (69 cm)||26.38 in (67 cm)|
|8 months||27.95 in (71 cm)||27.17 in (69 cm)|
|9 months||28.35 in (72 cm)||27.56 in (70 cm)|
|10 months||28.74 in (73 cm)||28.15 in (71.5 cm)|
|11 months||29.33 in (74.5 cm)||28.74 in (73 cm)|
|12 months||29.92 in (76 cm)||29.13 in (74 cm)|
It is important to note that the above numbers represent averages. Children can be healthy at a wide range of heights. No matter how long a baby is at birth, they are likely to grow at similar rates to other babies.
This means that if a baby is born longer than average, they are likely to stay this way during their first or second year of growth.
A baby’s growth in length during the first year almost always depends on their length at birth, unless they have significant issues, such as feeding difficulties or medical problems, that may cause insufficient length or weight gain.
For this reason, length alone does not reveal whether a baby is healthy. Weight is also an important consideration, especially since many newborns lose some weight after birth. Doctors will also look at factors, including gestational age and how much and how well a baby is eating.
Most healthy babies follow a similar growth pattern during the first year of life. After that, growth rates vary, and a baby’s length is not usually a good predictor of their height as an adult.
A parent or caregiver who takes their baby in for measuring should also know that an infant’s measured length can vary according to who is doing the measuring and how much the baby is moving around at the time. Research shows that length measurements during infant well checkups have the
Therefore, if it seems there is an unexpected change in a baby’s length from one visit to the next, it can be due to differences in measuring. A person may wish to request another measurement during the visit or at the next one to rule out a legitimate issue.
Babies who are much smaller or larger than average in weight and length are more likely to experience health complications.
However, there is a wide variation in healthy birth weights, so parents and caregivers may not need to have concerns. A doctor will assess how closely they need to monitor a baby’s growth over time. Growth rates for length are fairly predictable among babies in the first year of life. Doctors are more interested in a baby’s overall growth pattern than their length.
A child who falls below the
However, this may not be apparent immediately. A baby who will be a tall adult may have a shorter length at birth and in the first year or two of life.
Numerous other factors may affect a child’s height, including:
- Genetics: Children are likely to be a similar height to their biological parents.
- The pregnancy: Research
showsthat factors, such as maternal anemia, high blood pressure, gestational diabetes, or obesity, may impact a baby’s growth after birth.
- Nutrition: Following a nutritious diet supports healthy growth.
- Hormones: Some children with hormonal imbalances grow slowly or more quickly than their peers.
- Health: A baby whose growth slows down that they fall into a much lower length group or whose length is persistently at a lower level may have a health issue. Some children with certain genetic conditions, such as Down syndrome,
may besmaller than others.
- Medications: Some medications, such as steroids, including prednisone,
People often do not see the effect of these issues on height in the first year of life.
During the first year of life, children should see their pediatrician at least seven times to monitor growth and overall health.
However, doctors’ recommendations may vary slightly. In general, a pediatrician will want to examine the baby at the following times in the first year:
- 3–5 days old
- 1 month old
- 2 months old
- 4 months old
- 6 months old
- 9 months old
- 12 months
A healthcare professional may recommend more frequent visits for a baby who loses a lot of weight after birth or has an unusual growth pattern.
In the early weeks of life, it can be difficult for parents or caregivers to know how much to feed a newborn. If the baby loses weight after birth, there could be feelings of pressure to help them regain the weight as quickly as possible, especially if the infant was born prematurely or has other health risk factors.
However, the amount of food newborns eat affects their weight much more than their length in the early stages of life. Insufficient weight gain needs to be present for a long time in infants before it affects their length.
Insufficient growth in length by itself in the first year is very uncommon and would more likely be due to a genetic syndrome or other uncommon condition.
How much should breastfed babies eat?
Most breastfed newborns eat every
Since a nursing person cannot measure how much milk they are giving the baby, they can gauge whether the baby is getting enough milk by looking at the frequency of nursing and diaper changes. These indicators include the following:
- The baby is nursing at least 8–12 times in 24 hours
- By day 2, the baby should have at least two wet diapers in 24 hours. By day days 3 and 4, at least three or more wet diapers, and by day 5, at least six or more wet diapers.
- By day 4, at least 3–5 bowel movements a day.
- The baby is gaining weight.
How much should formula-fed babies eat?
Formula-fed babies may eat less frequently than breastfed babies. After the first few days, people typically feed formula-fed babies with
Like breastfed newborns, formula-fed infants should eventually eat 8–12 times in 24 hours, including at night. This will continue until they are approximately 6 months old when the child is ready to begin eating solid foods.
Like adults, babies are unique — there is no right or ideal length. As long as the infant is growing normally and does not suddenly fall well below their previous growth percentile, they are usually fine.
Before the age of 2 years, doctors usually measure a baby’s length lying down. After the age of 2 years, when a child is able to stand, a doctor can begin to
Caregivers should know that at this stage, doctors may switch from the WHO growth charts to the Centers for Disease Control and Prevention’s (CDC) growth reference charts.
Since standing height measures slightly less than recumbent length, a child’s classification may change slightly at this point. The pediatrician can help parents and caregivers answer questions about length, growth, nutrition, and more.