Corrected age: what is it?

Corrected age, or adjusted age, calculates your premature baby’s age by taking their prematurity into account.

Corrected age is your baby’s age now (their chronological age) in weeks or months minus the number of weeks or months early they were born. For example, a 1-year-old who was born 3 months early would have a corrected age of 9 months – that is, 9 months post their due date.

If your baby hasn’t reached their due date yet, you can work out your baby’s corrected age using their age now in weeks plus the number of weeks you were pregnant when your baby was born. For example, an 8-week-old who was born 10 weeks early (when you were 30 weeks pregnant) would have a corrected age of 38 weeks.

If you’re giving your child a first birthday party, you should celebrate their birthday one year from when they were born, regardless of corrected age!

Why corrected age is important

Corrected age helps if you or your doctor are trying to work out whether your premature baby’s growth and development is tracking in a typical way, especially in the early years.

For example, if someone notices that your baby is 6 months old but not sitting up yet, you could explain that your baby was born 3 months early. This means your baby’s corrected age is only 3 months and you wouldn’t expect them to be able to sit up at 3 months. But your baby is probably doing everything a 3-month-old usually does.

Corrected age is most relevant during your child’s early years, because it might explain things that look like slow growth or delays in development in these years.

Who to tell about your child’s corrected age

It’s a good idea to tell early childhood educators or teachers, health professionals and anyone who cares for or works with your child that your child was born prematurely. These people will probably also find it useful to know how many weeks early your child was born.

If you’re worried about learning or developmental problems after your child starts school, it will help school teachers to know that your child was born early.

There isn’t a set age when you should stop correcting a child’s age for prematurity. But most health professionals recommend correcting until your child is at least 2 years old.

How corrected age affects your child’s play and interactions

You might notice that other babies of the same chronological age can do more than your premature baby when they play and interact with you and others. But if you think in terms of corrected age, you might find that what your child can do is just right for their age.

Like all children, your premature child will learn from having plenty of different things to play with, do and see – for example, reading, going to the park, playing with you and others, and so on.

All these different and stimulating experiences help your child’s brain to develop.

Corrected age and starting child care, preschool or school

Your child might start preschool and school based on their chronological age, not their corrected age.

But a few months in age can make a difference to what children can do and what they’re expected to do, especially at preschool. Some parents of premature children decide to delay school for a year if their child’s corrected age is just below school entry age. This can give your child extra time to grow and develop the social skills they need for preschool and school.

If your child is assessed for any development delay, you can ask for the test results to be scored at both your child’s corrected and chronological ages.

When to have immunisations

Premature babies generally get the same immunisations at the same chronological age as babies born at term. Premature babies need the protection of immunisation because they’re more likely to get some infections.

If your baby was very premature, they might get their first immunisations while they’re still in hospital. They might also need an extra dose of some vaccines when they’re older.

It’s best to speak to your child’s GP or paediatrician about your child’s immunisation needs.