Your premature baby
The premature infant: How old is my baby?
- Chronological age is the age of the baby from the day of birth—the number of days, weeks or years old the baby is.
- Adjusted age is the age of the baby based on his due date. Health care providers may use this age when they evaluate the baby's growth and development. So, if a baby is 6 months old, but was born two months early, his adjusted age is 4 months.
What to say when someone asks
This is up to you.
- You can say, "He's 6 months old, but he was born two months early. That's why he looks like a 4-month-old."
- Or you can say, "He's 6 months old" and leave it at that.
Remember: When people ask about your baby, they usually are being kind, not nosy.
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.
Calculating your baby's adjusted age: Example
- Chronological age: 20 weeks
- The number of weeks your baby was premature: 6 weeks
- Subtract the number of weeks premature from the chronological age (this is your baby's adjusted age): 20 weeks minus 6 weeks equal 14 weeks.
- Divide your baby's adjusted age in weeks by 4 to determine your baby's adjusted age in months: 14 divided by 4 equals 3 ½ months.
See also: Share your story
How old is my baby?
- Age can be based on the baby’s birthday.
- Age can be based on the baby’s due date.
- Development time is unique to each baby.