Corrected age is a calculation used to assess a premature baby's development and growth. It is determined by subtracting the number of weeks a baby was born early from their actual age, relative to the 40-week full-term mark.

For instance, a baby born at 32 weeks, which is eight weeks early, will have a corrected age of about two months when their actual age is four months. Similarly, a baby born at 28 weeks will have a corrected age of approximately one month when they reach an actual age of four months.

It is important to note that corrected age is not a legal age and is not used to change a child's birth date. Instead, it is a calculation tool used to assess a child's development and growth during their early years, typically the first two years of life.

A nurse in the Neonatal Department cares for a premature baby. Illustration: Tam Anh General Hospital

Corrected age helps doctors monitor a child's motor skills, language development, communication, and social interaction milestones. Parents should avoid concluding that their child has developmental delays if a premature baby has not yet reached a milestone when calculated by their actual age. Doctors will consider the corrected age alongside the baby's gestational age at birth, previous developmental progress, and current health status.

A premature baby is considered to be progressing well when they maintain an appropriate growth trajectory, rather than necessarily achieving the same weight or height as a full-term baby of the same chronological age. Their growth can be evaluated using specific growth charts designed for premature infants during the initial period after birth.

Not all aspects of a premature baby's care are based on corrected age. Vaccinations, for example, are administered according to the child's actual age, counted from their birth date. Therefore, parents should not independently postpone their child's vaccination schedule but must adhere to their doctor's guidance.

When taking a child for a medical examination, parents should provide the doctor with the birth date, gestational age at birth, and the estimated due date to ensure all necessary information is available. Depending on the purpose of the visit, the doctor may use actual age, corrected age, or a combination of both. For instance, when a child has an acute illness, their actual age and current health condition are crucial for assessment.

Dr. Nguyen Van Toan

Deputy Head of Neonatal Department

Tam Anh General Hospital Hanoi