What is the Average Length of a Newborn Baby

As a new or even existing mom, the question “What is the Average Length of a Newborn Baby” will swirl around your mind, not only because you need to purchase baby clothes, but because you want to imagine the little life you have created in your arms! Newborn babies generally follow a predictable level of growth within their first year. Individuals are able to track the length of their babies by using average growth charts. A baby that has been born full-term has an average length of 19-20 inches at birth. This is 48.2-50.8 centimeters. It is, however, possible for babies to be born with a length of around 18.5-20.9 in, or 47-53 cm. Babies that have been born male are often slightly longer than babies that have been born female. When measuring a baby’s length, the doctor measures from the top of the baby’s head to the foot’s heel. In this article, we’ll discuss the average baby length, as well as what it may mean if your baby is shorter or longer than average and when would be an appropriate time to contact a doctor. 

Baby Sizes Throughout Their First Year

What is the Average Length of a Newborn Baby | Healthier Baby Today

The World Health Organization (WHO) is responsible for publishing standard infant growth charts that have been set up according to the expected growth of children in six countries, this includes the United States, in optimal growth environments. This also includes those who breastfeed. 

An important thing to remember is that many individuals use the terms “length” and “height” interchangeably. Doctors will, however, measure babies’ lengths lying down until the age of 2 years old. Experts call this recumbent length in measurement terms. This is very different from height, which doctors will only begin to measure after the age of 2 years when a child has the ability to stand. 

Within the first year of a baby’s life, they typically grow in length by 50%. According to the growth chart created by the WHO, “What is the Average Length of a Newborn Baby” lengths for babies that were born male, as well as babies who were born female, by month, are as follows:

  • Birth: Male Baby 19.69 in (50 cm), Female Baby 19.29 in (49 cm)
  • 1 month: Male Baby 21.65 in (55 cm), Female Baby 21.26 in (54 cm)
  • 2 months: Male Baby 23.03 in (58.5 cm), Female Baby 22.44 in (57 cm)
  • 3 months: Male Baby 24.21 in (61.5 cm), Female Baby 23.62 in (60 cm)
  • 4 months: Male Baby 25.20 in (64 cm), Female Baby 24.41 in (62 cm)
  • 5 months: Male Baby 25.98 in (66 cm), Female Baby 25.20 in (64 cm)
  • 6 months: Male Baby 26.77 in (68 cm), Female Baby 25.48 in (66 cm)
  • 7 months: Male Baby 27.17 in (69 cm), Female Baby 26.38 in (67 cm)
  • 8 months: Male Baby 27.95 in (71 cm), Female Baby 27.17 in (69 cm)
  • 9 months: Male Baby 28.35 in (72 cm), Female Baby 27.56 in (70 cm)
  • 10 months: Male Baby 28.74 in (73 cm), Female Baby 28.15 in (71.5 cm)
  • 11 months: Male Baby 29.33 in (74.5 cm), Female Baby 28.74 in (73 cm)
  • 12 months: Male Baby 29.92 in (76 cm), Female Baby 29.13 in (74 cm)

The numbers above represent averages. Children may be healthy at a wide range of heights. It does not matter how long a baby is at birth. They are most likely going to grow at a similar rate to other babies. Therefore, if a baby has been born longer than average, they are very likely to stay that way during its first or second year of growth.

Your baby’s growth in length during their first year generally depends on their length at birth, unless they have issues that are significant, such as difficulties feeding or other medical problems that may cause insufficient weight or length gain. 

Because of this, length alone cannot reveal whether a baby is healthy or not. Weight is an essential factor that is needed to consider, especially since most newborns lose some weight after birth. Doctors may also look at various factors such as gestational age and how much as well as how well a baby is eating. 

What Could it Mean if a Baby is Small or Large?

What is the Average Length of a Newborn Baby | Healthier Baby Today

“What is the Average Length of a Newborn Baby” will depend on numerous factors; however, there is an average range your little one will fall into! Babies that are much smaller or larger than the average in weight and length are likely to experience health complications. There is, however, a wide variation in healthy birth weights. Thus, you may not need to have concerns. A doctor will assess how closely monitoring a baby’s growth over time may need to be. The growth rates are often fairly predictable among babies within their first year of life. The overall growth pattern of a baby is of more interest for a doctor than their length alone. 

The factors that may affect a child’s height include:

  • Genetics: Children are often more likely to be of a similar height to their biological parents. 
  • The pregnancy: Research has shown that factors such as maternal anemia, high blood pressure, gestational diabetes as well as obesity may affect a baby’s growth after birth. 
  • Nutrition: Healthy growth is supported by following a nutritious diet. Hormones: Children who have hormonal imbalances may grow slowly or more quickly than their peers. 
  • Health: When a baby’s growth slows down so much that they start to fall into a lower length group, it may have a health issue. There are certain genetic disorders, such as Down syndrome, which may often be smaller than others. 
  • Medications: There are medications that may stunt growth, such as steroids. This includes prednisone. 

When to See a Doctor

What is the Average Length of a Newborn Baby | Healthier Baby Today

During your little ones’ first year of life, your pediatrician will need to see your baby at least seven times in order to monitor growth as well as overall health. The doctor’s recommendations, however, may vary slightly. A pediatrician will generally want to examine your baby at the following times during their first year:

  • 3–5 days old
  • 1 month old
  • 2 months old
  • 4 months old
  • 6 months old
  • 9 months old
  • 12 months

More frequent visits may be recommended by a healthcare professional for a baby who has lost a substantial amount of birth weight or has an unusual growth pattern. 

A Short SummaryWhat is the Average Length of a Newborn Baby

What is the Average Length of a Newborn Baby | Healthier Baby Today

Similar to adults, babies are very unique. There are no right or ideal lengths. Infants are considered fine as long as they are growing normally and do not suddenly fall below their previous growth percentile. Before a baby turns two, doctors generally measure the length of the baby while they are lying down. After the age of 2 years, when the child can stand, a doctor may begin to measure their standing height. You should now remember that at this stage, doctors may switch from the growth charts presented by WHO to the growth charts presented by the Centers for Disease Control and Prevention (CDC) for reference. A standing height measures slightly less than a recumbent length. Therefore, a child’s classification may have a slight change at this point. Your pediatrician will ensure any needed questions are answered you have with regard to length, growth, and nutrition. 

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