Adjusted Age in Premature Infants

Newborn baby sleeping in incubator
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Because your child was born early, doctors use their adjusted age, also called corrected age, to determine when they should reach certain milestones. Adjusted age is the age a preemie would be if he had been born on his due date. Adjusted ages are useful when evaluating a preemie's size and development. Chronological age is not used as a benchmark because many preemies may not have developed functions that many babies born at term have, such as breathing on their own, maintaining their body heat, etc.

Calculating Adjusted Age of a Preemie

When you are figuring out your baby's adjusted age, figure out how many weeks or months early your baby was born, and subtract that number from his actual age. For instance:

  • A baby who is 8 months old but was born a month early would have a corrected age of 7 months old.
  • A baby who is 5 months old but was born 6 weeks early would have a corrected age of 3 1/2 months old.

By subtracting the months a child was born early, you allow them a template more appropriate to reach certain milestones. For example, if a baby is 4 months old but was born 2 months early, for example, his weight and development may be closer to that of a 2-month-old baby, and thus his corrected age is 2 months. Many preemies may exceed expectations and skew closer to their actual birth date, while others fall behind even their adjusted age projections.

How Long to Use Adjusted Age

There isn't any hard and fast rule about how long you should use your preemie's corrected age. But when gauging your child's development, most doctor's recommend using your baby's adjusted age instead of his actual age until he turns 2 years old, or until his size and development catch up to what they should be if he had been born at term. If your preemie is doing everything that a full-term baby the same age can do, then it's probably safe to stop using his corrected age. If your preemie is older than 2 but still seems younger, then it would make sense to continue using his corrected age.

Your child may have a growth spurt or developmental push between the ages of 1 and 2 that may catch him up to normal numbers for his actual birth age. If your child is still behind after 2 years old, doctors will no longer chart your baby according to normal babies, but instead will focus on the rate of growth expected for your child.

Explaining Adjusted Age to Loved Ones

Your friends and family may not understand adjusted age, so while it makes sense to you to share it, be prepared to explain the difference between corrected age and chronological, or actual age. Many people will be confused and question you as to its importance. Help them understand that it is just used to help you monitor your babies growth. Just as it is with babies born on their due date, there is no guarantee that your child will follow the adjusted age growth chart. The most important thing to remember is to stay attentive and interactive with your preemie. Even if they seem too small to do certain things, allowing them to play and interact with you will help move them toward normal development.

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  1. American Academy of Pediatrics. Corrected Age For Preemies. Updated December 10, 2018.