Adjusting age for preemies
Babies who are born prematurely often have two ages: Chronological age is the age of the baby from the day of birth—the number of days, weeks or years old the baby actually has been in the outside world. Adjusted age is the developmental age of the baby based on his due date.
To calculate adjusted age, you take your premature baby’s chronological age (for example, 20 weeks) and subtract the number of weeks premature the baby was (born 6 weeks early). In this example, the baby’s adjusted age would be 14 weeks. Health care providers may use the adjusted age when they evaluate the baby’s growth and development.
Barring serious physical or neurological injury, most premature babies “catch up” to their peers, developmentally, in two to three years. After that, any differences in size or development are most likely due to individual differences, rather than to premature birth. Some very small babies take longer to catch up. You can stop adjusting your baby’s age when it feels most comfortable to you.