Physical Development

Should I Use Adjusted Age for My Preemie's Milestones?

Medically reviewed by Dr. Sarah Chen, MD, FAAP · Board-Certified Pediatrician

Content reviewed against published AAP, NIH, March of Dimes guidelines

Editorial policy

Last reviewed:

Your baby's physical development is unique, and concerns about should i use adjusted age for my preemie's milestones, here is what you need to know.

The short answer

Yes — for premature babies, developmental milestones should be assessed using adjusted (corrected) age, not chronological age, until at least 2 years of age. Adjusted age is calculated by subtracting the number of weeks your baby was born early from their actual age. For example, a 6-month-old born 2 months early would have an adjusted age of 4 months, and should be assessed against 4-month milestones. Most pediatricians use adjusted age for developmental assessment through age 2-3, and for growth charts through age 2.

Key takeaways

  • Yes — for premature babies, developmental milestones should be assessed using adjusted (corrected) age, not chronological age, until at least 2 years of age. Adjusted age is calculated by subtracting the number of weeks your baby was born early from their actual age. For example, a 6-month-old born 2 months early would have an adjusted age of 4 months, and should be assessed against 4-month milestones. Most pediatricians use adjusted age for developmental assessment through age 2-3, and for growth charts through age 2.
  • Usually normal when: Your preemie is meeting milestones appropriate for their adjusted age, even if they seem "behind" compared to same-age term babies
  • Call your doctor if: Your baby has seizures or unusual repetitive movements — seek immediate medical evaluation
  • Varies by age — see the age-by-age breakdown below
“Supervised tummy time is recommended daily from the time the baby comes home from the hospital to help prevent flat head syndrome and to strengthen neck and shoulder muscles.”
— Back to Sleep, Tummy to Play, American Academy of Pediatrics (AAP)

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What Parents Should Know

According to AAP, NIH, March of Dimes guidelines, yes — for premature babies, developmental milestones should be assessed using adjusted (corrected) age, not chronological age, until at least 2 years of age. Adjusted age is calculated by subtracting the number of weeks your baby was born early from their actual age. For example, a 6-month-old born 2 months early would have an adjusted age of 4 months, and should be assessed against 4-month milestones. Most pediatricians use adjusted age for developmental assessment through age 2-3, and for growth charts through age 2. At 0-6 months corrected age, in the early months, the difference between chronological and adjusted age is most significant. A baby born at 28 weeks has 3 months of "catch-up" to do. Compare your baby's skills to their adjusted age, not their birth date. It is common for well-meaning family members or even some healthcare providers to forget to use adjusted age — advocate for your baby by reminding them. Most preemies make rapid developmental progress during this period. It is generally considered normal when your preemie is meeting milestones appropriate for their adjusted age, even if they seem "behind" compared to same-age term babies. However, you should contact your pediatrician promptly if your baby has seizures or unusual repetitive movements — seek immediate medical evaluation.

Sources: [1], [2], [3]

Normal vs. Concerning

Usually Normal
Worth Discussing
Your preemie is meeting milestones appropriate for their adjusted age, even if they seem "behind" compared to same-age term babies
Your baby has seizures or unusual repetitive movements — seek immediate medical evaluation
Your baby is progressing steadily, even if the pace is slower than term babies
Your baby suddenly stops feeding, becomes floppy or unresponsive — call 911
Your preemie catches up in some areas faster than others — this uneven development is typical
Your baby is not meeting milestones even when adjusted age is used

By Age

What to expect by age

0-6 months corrected age

In the early months, the difference between chronological and adjusted age is most significant. A baby born at 28 weeks has 3 months of "catch-up" to do. Compare your baby's skills to their adjusted age, not their birth date. It is common for well-meaning family members or even some healthcare providers to forget to use adjusted age — advocate for your baby by reminding them. Most preemies make rapid developmental progress during this period.

6-12 months corrected age

Many preemies begin to close the developmental gap during this period, though the rate of catch-up varies. Motor milestones (sitting, crawling) may be slightly delayed even by adjusted age, particularly for babies who had a long NICU stay or medical complications. Physical therapy can help if your baby is behind. Social and cognitive development often catches up faster than motor skills.

12-24 months corrected age

By 12-18 months adjusted age, many preemies have caught up to their full-term peers in most developmental areas. Walking may be later by adjusted age for some preemies, particularly those born very early or those with neurological concerns. Language development should be tracked carefully — early intervention for speech delays is highly effective.

2-3 years

Most healthcare providers stop using adjusted age by age 2-3, as the difference becomes less significant. By this point, the majority of preemies without major complications are developmentally similar to their peers. If your child still has significant delays at this age, continued developmental support and evaluation is appropriate. Some subtle differences in executive function or attention may persist into school age and benefit from educational support.

What to Tell Your Pediatrician

  • Describe when you first noticed should i use adjusted age for my preemie's milestones and how it has changed over time.
  • Note your baby's current age and which age-specific patterns you are seeing.
  • Mention if your baby is not meeting milestones even when adjusted age is used.
  • Mention if your baby seems to have lost skills they previously had (regression).
  • Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
  • Bring a list of any questions or observations you want to discuss at the appointment.

What Should You Do?

When to take action

Probably normal when...
  • Your preemie is meeting milestones appropriate for their adjusted age, even if they seem "behind" compared to same-age term babies
  • Your baby is progressing steadily, even if the pace is slower than term babies
  • Your preemie catches up in some areas faster than others — this uneven development is typical
Mention at your next visit when...
  • Your baby is not meeting milestones even when adjusted age is used
  • Your baby seems to have lost skills they previously had (regression)
  • You notice significant asymmetry — your baby strongly favors one hand or one side of the body before 12 months
  • Your baby is not babbling, making eye contact, or showing social engagement by 6 months adjusted age
Act now when...
  • Your baby has seizures or unusual repetitive movements — seek immediate medical evaluation
  • Your baby suddenly stops feeding, becomes floppy or unresponsive — call 911

What You Can Do at Home

  • Keep track of when you notice should i use adjusted age for my preemie's milestones — noting the time of day, duration, and any triggers can help your pediatrician.
  • Remember that your preemie is meeting milestones appropriate for their adjusted age, even if they seem "behind" compared to same-age term babies — this is generally within the range of normal.
  • At 0-6 months corrected age, focus on observation rather than intervention unless your pediatrician advises otherwise.
  • Provide plenty of supervised floor time and tummy time to support your baby's physical development.
  • While monitoring at home, seek immediate care if your baby has seizures or unusual repetitive movements — seek immediate medical evaluation.

I Can't Stop Worrying Something Is Wrong After the NICU

Vulnerable child syndrome describes a pattern of persistent, excessive worry about a child's health that continues long after the child has recovered from a serious illness or NICU stay. Parents may overprotect, make excessive doctor visits, and have difficulty letting their child take age-appropriate risks. This is a normal response to a traumatic experience, but when it significantly impacts daily life and the child's development, professional support can help you rebuild trust that your baby is okay.

My Baby Was Diagnosed with PVL (Periventricular Leukomalacia)

Periventricular leukomalacia (PVL) is a type of white matter brain injury that occurs most commonly in premature babies. It involves damage to the tissue around the brain's ventricles, which carries nerve fibers controlling motor movements. PVL is one of the most common brain injuries in preterm infants and can range from mild (small focal areas) to more extensive involvement. While PVL is associated with an increased risk of cerebral palsy and developmental delays, outcomes vary widely depending on severity, and early intervention can make a significant difference.

My Baby Has BPD (Bronchopulmonary Dysplasia) — Chronic Lung Disease

Bronchopulmonary dysplasia (BPD) is a chronic lung condition that primarily affects premature babies who needed oxygen or ventilator support after birth. The immature lungs become inflamed and scarred, leading to ongoing breathing difficulties. BPD ranges from mild (needing oxygen briefly after 36 weeks corrected age) to severe (requiring long-term respiratory support). While BPD is a serious diagnosis, most children's lungs continue to grow and improve over the first 2-3 years of life, and many outgrow their oxygen needs entirely.

NICU Parent Trauma and Stress

Having a baby in the NICU is one of the most stressful experiences a parent can face. Research shows that up to 70% of NICU parents experience clinically significant anxiety or depression, and a substantial number develop PTSD symptoms. The helplessness, fear, separation from your baby, and disruption of expected parenthood are legitimately traumatic. Your pain is real and you deserve support.

Milestone

Month-by-Month Development

Detailed monthly development guides from birth through 24 months.

Guide

When to Call the Doctor

General guide on when to call the pediatrician, visit urgent care, or go to the ER.

Frequently asked questions

Is should i use adjusted age for my preemie's milestones normal?
Yes — for premature babies, developmental milestones should be assessed using adjusted (corrected) age, not chronological age, until at least 2 years of age. Adjusted age is calculated by subtracting the number of weeks your baby was born early from their actual age. For example, a 6-month-old born 2 months early would have an adjusted age of 4 months, and should be assessed against 4-month milestones. Most pediatricians use adjusted age for developmental assessment through age 2-3, and for growth charts through age 2.
When should I call the doctor about should i use adjusted age for my preemie's milestones?
Your baby has seizures or unusual repetitive movements — seek immediate medical evaluation Your baby suddenly stops feeding, becomes floppy or unresponsive — call 911
When is should i use adjusted age for my preemie's milestones normal?
Your preemie is meeting milestones appropriate for their adjusted age, even if they seem "behind" compared to same-age term babies Your baby is progressing steadily, even if the pace is slower than term babies Your preemie catches up in some areas faster than others — this uneven development is typical
What causes should i use adjusted age for my preemie's milestones?
Yes — for premature babies, developmental milestones should be assessed using adjusted (corrected) age, not chronological age, until at least 2 years of age. Adjusted age is calculated by subtracting the number of weeks your baby was born early from their actual age. For example, a 6-month-old born 2 months early would have an adjusted age of 4 months, and should be assessed against 4-month milestones. Most pediatricians use adjusted age for developmental assessment through age 2-3, and for growth charts through age 2. Common explanations include: Your preemie is meeting milestones appropriate for their adjusted age, even if they seem "behind" compared to same-age term babies. Your baby is progressing steadily, even if the pace is slower than term babies.
What should I mention to my pediatrician about should i use adjusted age for my preemie's milestones?
You should mention should i use adjusted age for my preemie's milestones at your next visit if: Your baby is not meeting milestones even when adjusted age is used. Your baby seems to have lost skills they previously had (regression). You notice significant asymmetry — your baby strongly favors one hand or one side of the body before 12 months.
Is should i use adjusted age for my preemie's milestones normal at 0-6 months corrected age?
In the early months, the difference between chronological and adjusted age is most significant. A baby born at 28 weeks has 3 months of "catch-up" to do. Compare your baby's skills to their adjusted age, not their birth date. It is common for well-meaning family members or even some healthcare providers to forget to use adjusted age — advocate for your baby by reminding them. Most preemies make rapid developmental progress during this period.
Is should i use adjusted age for my preemie's milestones normal at 6-12 months corrected age?
Many preemies begin to close the developmental gap during this period, though the rate of catch-up varies. Motor milestones (sitting, crawling) may be slightly delayed even by adjusted age, particularly for babies who had a long NICU stay or medical complications. Physical therapy can help if your baby is behind. Social and cognitive development often catches up faster than motor skills.
Should I go to the ER for should i use adjusted age for my preemie's milestones?
Seek emergency care if your baby has seizures or unusual repetitive movements — seek immediate medical evaluation, or if your baby suddenly stops feeding, becomes floppy or unresponsive — call 911. When in doubt, call your pediatrician's after-hours line for guidance.
Does should i use adjusted age for my preemie's milestones go away on its own?
In many cases, should i use adjusted age for my preemie's milestones resolves on its own, especially when your preemie is meeting milestones appropriate for their adjusted age, even if they seem "behind" compared to same-age term babies. By 2-3 years, most healthcare providers stop using adjusted age by age 2-3, as the difference becomes less significant. By this point, the majority of preemies without major complications are developmentally similar to their peers. If your child still has significant delays at this age, continued developmental support and evaluation is appropriate. Some subtle differences in executive function or attention may persist into school age and benefit from educational support.
AAPNIHMARCH OF DIMES

References

  1. [1]American Academy of Pediatrics. Developmental Follow-Up of Preterm Infants. HealthyChildren.org. AAP
  2. [2]National Library of Medicine. Developmental Follow-Up of Preterm Infants. Clinics in Perinatology, 2018. NIH
  3. [3]March of Dimes. Your Premature Baby's Growth and Developmental Milestones. March of Dimes

Doctor Visit Checklist

Bring this checklist to your next pediatrician visit to discuss Should I Use Adjusted Age for My Preemie's Milestones?.

Things to mention

  • Describe when you first noticed should i use adjusted age for my preemie's milestones and how it has changed over time.
  • Note your baby's current age and which age-specific patterns you are seeing.
  • Mention if your baby is not meeting milestones even when adjusted age is used.
  • Mention if your baby seems to have lost skills they previously had (regression).
  • Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
  • Bring a list of any questions or observations you want to discuss at the appointment.

Observations to share

  • Your baby is not meeting milestones even when adjusted age is used
  • Your baby seems to have lost skills they previously had (regression)
  • You notice significant asymmetry — your baby strongly favors one hand or one side of the body before 12 months

Urgent signs to report immediately

  • Your baby has seizures or unusual repetitive movements — seek immediate medical evaluation
  • Your baby suddenly stops feeding, becomes floppy or unresponsive — call 911

My notes

From ismybabyalright.com — free, evidence-based baby health guides

All content follows our editorial policy and is reviewed against published clinical guidelines.

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Related Resources

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Bottom line

Most cases of should i use adjusted age for my preemie's milestones are normal. Talk to your pediatrician if your baby has seizures or unusual repetitive movements — seek immediate medical evaluation.

Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.

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I Can't Stop Worrying Something Is Wrong After the NICU

Vulnerable child syndrome describes a pattern of persistent, excessive worry about a child's health that continues long after the child has recovered from a serious illness or NICU stay. Parents may overprotect, make excessive doctor visits, and have difficulty letting their child take age-appropriate risks. This is a normal response to a traumatic experience, but when it significantly impacts daily life and the child's development, professional support can help you rebuild trust that your baby is okay.

My Baby Was Diagnosed with PVL (Periventricular Leukomalacia)

Periventricular leukomalacia (PVL) is a type of white matter brain injury that occurs most commonly in premature babies. It involves damage to the tissue around the brain's ventricles, which carries nerve fibers controlling motor movements. PVL is one of the most common brain injuries in preterm infants and can range from mild (small focal areas) to more extensive involvement. While PVL is associated with an increased risk of cerebral palsy and developmental delays, outcomes vary widely depending on severity, and early intervention can make a significant difference.

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Bronchopulmonary dysplasia (BPD) is a chronic lung condition that primarily affects premature babies who needed oxygen or ventilator support after birth. The immature lungs become inflamed and scarred, leading to ongoing breathing difficulties. BPD ranges from mild (needing oxygen briefly after 36 weeks corrected age) to severe (requiring long-term respiratory support). While BPD is a serious diagnosis, most children's lungs continue to grow and improve over the first 2-3 years of life, and many outgrow their oxygen needs entirely.

NICU Parent Trauma and Stress

Having a baby in the NICU is one of the most stressful experiences a parent can face. Research shows that up to 70% of NICU parents experience clinically significant anxiety or depression, and a substantial number develop PTSD symptoms. The helplessness, fear, separation from your baby, and disruption of expected parenthood are legitimately traumatic. Your pain is real and you deserve support.

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