Real Age vs Corrected Age

Parents of premature babies not only have to struggle with life in the NICU but they also have to learn about “corrected age”. For some parents it can become confusing to understand what their babies corrected age is.

The gestational age of a baby is calculated from the first day of the mother’s last menstrual period. Conception probably takes place about 2 weeks after this date. The baby’s corrected age takes the gestational age into account. For example, if a baby was born at 32 weeks gestation and is now 4 weeks old, then his corrected age is 36 weeks gestation. This is useful in assessing how a baby is behaving and developing in relation to his age.

A full term pregnancy is estimated to be 40 weeks. The Corrected age is based on the age the child would be if the pregnancy had actually gone to term.


– Baby Harry was born at 27 weeks gestation
– He was 13 weeks premature (40 weeks – 27 weeks = 13 weeks)
– Today he is 6 months old – from the day he was actually born
– 6 months “real age” – 3 months premature
– Harry is 3 months corrected in age

Immunisations are generally given to the child using their “real age” & teeth grow by your child’s “real age”. This is a common question parents ask.

Assessment of growth, feeding skills, and development should be based on a “corrected age” for pre-term infants. Use of the actual date of birth to calculate age will lead to inappropriate assessment and advice. Parents report that health professionals frequently fail to take prematurity into account so be sure to remind them.

The subject matter provided in these articles is strictly for informational purposes alone and should never be used in the place of a doctor’s advice. Please ALWAYS contact your doctor if you ever have questions or need advice in any area where medical advice is needed or medication is suggested.