Corrected Age: One of The Areas Where Even The Pro's Get It Wrong

Corrected age: One of the areas where even the pro's get it wrong

How does corrected age work and how do I use it to track my baby's development?

OK, let's start at the very beginning.

Premature babies have 2 ages

Getting your baby’s age right is simple. Right?

Normally yes. But even professionals sometimes get it wrong when working with babies born prematurely.

Generally you just count the number of months, weeks and days from your baby’s date of birth to determine his age. But the age of premature babies work a little differently.

In fact, preemie babies have 2 ages…

  1. Normal chronological or calendar age, and...

  2. A corrected age

Your baby's calendar age

Calendar age is your child’s age calculated on his date of birth. As far as everyone is concerned, your baby only has this one age. That is the age that goes onto every imaginable form and paperwork during his lifetime.

But before we go to the second age, let’s first look at what qualifies as a premature baby.

What is a premature baby?

Full term pregnancy is accepted to be 40 weeks from the mother’s last menstrual period. So, all babies have a normal 40-week development period before birth. 

And any baby born before 37 full development weeks is seen as a premature baby.

What this simply means is that if 2 babies are born on the same day, but did not have the same development period in the womb, their developments would not be the same. In fact, not even closely similar.

Say baby Joe was a full term 40 week baby, whereas Sam was born at 34 weeks. Both of them were New Year babies… born 1 January. Now, on 31 May both of them are 5 months old. And Joe can roll over unaided, but Sam shows no signs of rolling over.

It is important to realize that Sam was actually born 6 weeks ahead of schedule. Sam should have been born only around 12 February (1 January plus 6 weeks). So on 1 January Sam started off with a stumbling block… he did not have the full development period in the womb.

Because of this shorter development period, Sam is slightly smaller than Joe. A further hindrance for a premature baby like Sam is that he initially grows and develops at a slower rate than Joe.

At this stage you will agree with me that as long as you keep on comparing Sam and Joe’s development, Sam will in all probability always be behind… at least for the first two years.

Calculating the second age

One way of realistically determining how well Sam is developing is to use Corrected Age (CA). Quite often this is also known as Gestationally Corrected Age (GCA) or sometimes just Gestational Age (GA).

All these terms are based on the age the premature baby would be if the pregnancy had been 40 weeks. It is a calculated age to compensate for a premature baby’s shorter development period in the womb.

CA (weeks or months) = calendar age (weeks or months) – period prematurely born (weeks or months)

If we now look at Sam, his corrected age on 31 May is =

5months (on 31 May) – 1.5months (born 6 weeks prematurely) = 3.5months

Using Sam’s CA immediately means that you don’t expect Sam to do the same things that Joe can already do. The fact that Sam is not rolling over on 31 May is therefore not a big concern yet. 

One caveat about using CA…

It only works for babies born before 37 weeks. It does not apply to babies born close to the 40 week full term development period.

Once you know how to calculate your premature baby’s CA, I suggest you do the following:

  1. Go to the baby development chart

  2. Use the CA and realistically determine what your baby’s development should really be

  3. Only now decide how to proceed...

For more helpful advice about Corrected Age and Premature Babies, click here