What Is Corrected Age for a Premature Baby?

If your baby was born prematurely, you may hear health professionals talk about both their actual age and their corrected age.

Corrected age helps us consider a premature baby's growth and development based on when they were expected to be born, rather than only using the date they were actually born.

This is particularly important when looking at early developmental milestones such as head control, tummy time, rolling, sitting, crawling and walking.

What does corrected age mean?

A full-term pregnancy is approximately 40 weeks.

If your baby was born before 37 weeks, they were born prematurely. Their corrected age takes into account the number of weeks they were born before their expected due date.

A simple way to calculate it is:

Corrected age = actual age − number of weeks premature

For example, if your baby:

• was born at 32 weeks gestation

• was therefore approximately 8 weeks early

• and is now 6 months old

their corrected age is approximately 4 months.

Although your baby has been in the world for six months, when considering their early development, we would generally compare them with a baby of approximately four months.

Why do we use corrected age for premature babies?

Those extra weeks make a significant difference during infancy.

Consider two babies who were born on the same day. One was born at 40 weeks gestation and the other at 30 weeks.

When they are both three months old by the calendar, the baby born at 30 weeks has only been past their expected due date for approximately two weeks.

It would therefore not be appropriate to expect the two babies to demonstrate the same developmental skills.

Using corrected age gives us a fairer and more meaningful way of looking at a premature baby's development.

Should I use corrected age for developmental milestones?

Yes. Corrected age should be considered when looking at the development of babies who were born prematurely.

This includes skills such as:

• smiling and interacting

• head control

• reaching and bringing hands together

• tummy time

• rolling

• sitting

• crawling

• pulling to stand

• standing

• walking.

For example, if your baby is 7 months actual age but 5 months corrected age, it is generally more appropriate to consider their motor skills in relation to a 5-month-old baby.

This can be reassuring for parents who may otherwise feel that their premature baby is "behind".

How long do we correct a premature baby's age?

Corrected age is commonly used when assessing growth and development during the first two years of life.

Queensland Health guidance recommends allowing for gestational age when assessing the growth and development of children born prematurely, particularly during the first two years.

Exactly how long corrected age remains clinically relevant can depend on how prematurely your baby was born, their medical history and the aspect of development being assessed.

Your paediatrician, child health nurse, physiotherapist or other health professional can advise you about how corrected age should be applied for your individual baby.

Does my premature baby need to catch up?

It is usually more helpful not to think of corrected age as giving your baby a deadline to "catch up".

Many premature babies gradually close the developmental difference between themselves and babies born at term. However, development varies considerably between children.

What is most important is that your baby is continuing to develop new skills and showing progression over time.

For a premature baby, we are interested not only in when they achieve a milestone, but also in how they move and how their movement is developing.

Are premature babies more likely to have developmental difficulties?

Many babies who are born prematurely go on to develop typically.

However, being born prematurely—particularly very or extremely prematurely—is associated with an increased risk of developmental and neurological difficulties.

This is one reason developmental follow-up can be important for some premature babies.

Rather than waiting until a significant delay becomes obvious, developmental surveillance can help identify more subtle differences in movement and development earlier.

What developmental assessments can be used for premature babies?

For babies born prematurely, particularly those who have spent time in a Special Care Nursery (SCN) or have other developmental risk factors, recognised standardised assessments can provide valuable information about how their movement and nervous system are developing.

At Babies on the Move, early infant development and developmental follow-up are particular areas of interest for us. We see babies in hospital Special Care Nursery settings and also follow babies after discharge into the community.

Importantly, we use many of the same evidence-based developmental and neurological assessments used in tertiary hospital follow-up programs, helping provide continuity between hospital-based care and community developmental follow-up.

The assessment we use depends on your baby's age, corrected age, medical history and individual developmental needs.

General Movements Assessment (GMA)

The General Movements Assessment (GMA) is an observational assessment of a young baby's spontaneous movements.

It is particularly useful during the first few months of life and can provide important information about the developing nervous system before many traditional motor milestones have emerged.

The GMA is internationally recognised as an important assessment for the early identification of babies at increased risk of cerebral palsy, particularly when considered alongside neurological assessment and, where available, neuroimaging.

Hammersmith Infant Neurological Examination (HINE)

The Hammersmith Infant Neurological Examination (HINE) is a structured neurological assessment used in infants from approximately 2 to 24 months of age.

It assesses areas including:

• posture

• movements

• muscle tone

• reflexes and reactions

• cranial nerve function

• symmetry.

Rather than simply recording whether a baby has achieved a milestone, the HINE provides information about how neurological function and movement patterns are developing over time.

Alberta Infant Motor Scale (AIMS)

The Alberta Infant Motor Scale (AIMS) is a standardised assessment of gross motor development during infancy.

It looks at the movements and positions a baby demonstrates naturally in:

• lying on their tummy

• lying on their back

• sitting

• standing.

The AIMS helps us monitor gross motor development and progression over time, while taking corrected age into account where appropriate.

Why might we use more than one assessment?

No single assessment can provide a complete picture of a baby's development.

For babies at increased developmental risk, best practice is to consider information from several sources. Depending on the baby, this may include spontaneous movement assessment, neurological examination, gross motor assessment, medical and neonatal history, clinical observation and neuroimaging when available.

For example, a baby may have a General Movements Assessment during the early months, followed by a HINE as they grow, while the AIMS may be used to monitor developing gross motor skills.

We also continually assess functional areas such as symmetry, strength, posture, muscle tone and emerging movement skills.

Looking at development over time gives us a much clearer picture than relying on a single milestone or assessment score.

Our experience with premature and high-risk babies

Our physiotherapists have extensive experience working with babies who have a history of:

• prematurity

• low birth weight or growth restriction

• Special Care Nursery admission

• complicated pregnancy or birth

• neurological concerns

• differences in muscle tone or movement

• delayed or asymmetrical motor development.

Because premature infant development is an area we work with regularly, our aim is not simply to determine whether your baby is reaching milestones at the expected time.

We look at how your baby moves, the quality and symmetry of their movement, their neurological development and how their skills are progressing over time.

This allows us to identify when additional support may be helpful, while also providing reassurance when development is progressing well.

Premature Baby Physiotherapy & Developmental Follow-Up

Babies on the Move provides paediatric physiotherapy and developmental assessment for babies born prematurely across the Gold Coast, Tweed and Northern Rivers.

Our focus is on early identification, evidence-based assessment and practical strategies that can be incorporated into your baby's everyday play and family routines.

Evidence & References

World Health Organization Multicentre Growth Reference Study Group. WHO Motor Development Study: Windows of Achievement for Six Gross Motor Development Milestones. Acta Paediatrica. 2006;95(S450):86–95.

Queensland Health. Chronic Conditions Manual – Child Health Checks: Body Measurements. Guidance includes adjustment for gestational age when assessing children born prematurely.

Spittle AJ, Morgan C, Olsen JE, Novak I, Cheong JLY. Early Diagnosis and Treatment of Cerebral Palsy in Children with a History of Preterm Birth. Clinics in Perinatology. 2018;45(3):409–420.

Novak I, Morgan C, Adde L, et al. Early, Accurate Diagnosis and Early Intervention in Cerebral Palsy: Advances in Diagnosis and Treatment. JAMA Pediatrics. 2017;171(9):897–907.

World Health Organization. WHO Child Growth Standards – Motor Development Milestones.