How Long Is A Baby A Newborn – The World Health Organization (or WHO),  defines the time for what is considered a newborn from the time an infant arrives via the birth canal to 28 days.

Babies By AgeStartEnd
NewbornFrom Birth28 Days
Infant2nd Month1 Year
Toddler1 Year3 Year

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How Long Is A Baby A Newborn
What About Premature Babies
Newborn Developmental Growth Stages
How Long Are Newborn Clothes Used

Some say that babies are considered newborn from birth until two months. After that stage, they are referred to as infants until they turn one year.

Another opinion regarding the question, “How long is a baby a newborn?” cites babies from birth to three months as newborns by most parents though this is an assumption [1].

The Merriam-Webster Dictionary defines what is considered a newborn as a baby who was born recently without further explanation. There are no descriptive characteristics mentioned.

Birth height and birth weight help track growth and development but are not used as defining characteristics for the term [2].

There are a lot of valid points and discussions by doctors and parents following the growth of babies.

From a general viewpoint, the period in what is considered a newborn depends on the rate of their growth and development. Babies’ developmental patterns vary.

That is why after birth, babies undergo a newborn screening. These screenings check everything from reflexes to urine blockage to eye health.

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How Long Is A Baby A Newborn
A Word About Premature Babies

Premature babies are defined as babies born before 37 weeks of gestation.

Age must be adjusted when tracking a premature baby’s growth and development. Premature babies tend to have eating issues because their digestive tracts are not yet developed.

Problems can occur with both breast milk and formula.

This can affect blood glucose levels which in turn affect growth and development.

Premature babies can be a challenge because they require frequent feedings.

Parents feeding both breastfed babies and formula-fed babies can benefit from a lactation consultant.

Baby acne is also common in premature babies.

They require more sleep than others newborns and take frequent naps during the day.

They benefit from skin-to-skin contact. A premature baby’s eyes need special care as well.

Newborn diapers can be a challenge, and jaundice is another common condition in premature babies as their livers are still developing.

A traditional baby’s first bath may have to be delayed for a premature infant.

Often these babies are hooked up to monitors. Both premature and more developed newborns require special care to their umbilical cord.

How Long Is A Baby A Newborn
What About Premature Babies
Newborn Developmental Growth Stages
How Long Are Newborn Clothes Used


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Newborn Developmental Growth Stages
Newborn Developmental Growth Stages

Healthy newborns go through several developmental growth stages. These factors help determine whether a baby has outgrown the newborn stage.

Newborn Growth Stage #1

Newborns already have reflexes.

As such, they can be easily startled, arch their backs and react by moving their legs and arms by sound.

Newborns can feel when you stroke their big toes which is called the Babinski reflex.

Other reflexes include the tongue thrust and step reflexes.

Newborn Growth Stage #2

Babies who are one-week-old can lift their heads briefly when they are lying on their stomachs.

They can also move both of their arms and legs.

Although eyesight at this point is a bit blurry, objects that are placed close to their faces (eight to ten inches away) will appear clear.

They can identify faces and gestures.

Newborn Growth Stage #3

At three weeks old, babies can lift their heads for a few seconds while lying on their stomachs. At this point, a parent should do supervised tummy time, which is essential for the proper development of neck muscles. At this stage, babies love to play with their pacifiers.

Newborn Growth Stage #4

One-month-old babies enjoy looking and staring at faces.

They can focus on objects placed about 8 to 15 inches away from them.

Smiling, cooing and praying baby hands are common during this stage.

Newborn Growth Stage #5

Babies about to turn three months will respond to a smile in their direction.

They will smile back at you.

They progress from crying to making other sounds that often mimic vocalizations they have heard around them.

Lifting the head is also easier at this stage sometimes with the chest raised.

Newborn Growth Stage #6

By the third month, babies know how to laugh out loud. Sometimes, they may even squeal.

They will be able to look at and follow objects positioned at least six inches from their face that move from one side to another.

Additionally, three-month-old babies can lift their heads at around a 45° angle.

Other developments concerning movement include rolling over, reaching for objects and grasping a rattle.

Babies will also play and make a lot of silly and funny sounds.

A newborn sleep pattern will change as your baby grows past their newborn stage.

Older infants need less sleep than newborns.

These developments are clear indications that a baby has transitioned out of the newborn stage [3].

How Long Is A Baby A Newborn
What About Premature Babies
Newborn Developmental Growth Stages
How Long Are Newborn Clothes Used


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How Long Are Babies In Newborn Clothes
How Long Are Babies In Newborn Clothes?

The developmental factors that identify whether a baby is still considered a newborn do not have much to do with actual size.

This begs the question that parents need answered when it is time to do the shopping. How long are babies in newborn clothes?

An expectant parent often stocks up on newborn clothes sometimes several months ahead of the baby’s debut into the world.

As a result, the baby’s closet is filled to the brim by the time they arrive.

Ideally, it is time to switch to from newborn clothes to infant clothes when your baby starts to grow.

So, how long are babies in newborn clothes?

The length of time babies wears newborn clothes depends on how fast they grow and develop physically.

How Long Is A Baby A Newborn
What About Premature Babies
Newborn Developmental Growth Stages
How Long Are Newborn Clothes Used

How Long Is A Baby A Newborn Conclusion

The terms “infant” and “newborn” are sometimes used interchangeably.

However, there are differing opinions on the precise definitions of these words.

The scientific community uses developmental milestones as determinants for certain titles, but exact time requirements are difficult to ascertain as babies develop at different rates.

The question remains, “How long is a baby a newborn?”

Babies have varied growth and developmental patterns.

There does not seem to be common criteria for determining exactly when a baby stops being a newborn.

A three-month-old baby boy can exhibit newborn characteristics while a two-month-old baby boy may already show advanced development and should not be considered a newborn anymore.

It is a case-by-case situation.

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How Long Is A Baby A Newborn Resources:
[1]   World Health Organization; Infant, Newborn, February 2018.
[2]   Merriam-Webster; newborn.
[3]   Centers for Disease Control and Prevention; Infants (0-1 year of age).

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