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Preemie milestones: what to expect, by adjusted age

Last verified: July 11, 2026

The short answer

Your preemie is expected to reach the same milestones as any baby, on a different calendar: the one that starts at the due date. To check any milestone, use the adjusted age, which is your baby's age in weeks minus the weeks they were born early. The American Academy of Pediatrics says to do this until age 2, and most children born early have caught up by then.

Illustration of a rising milestone chart ending in a star

Every milestone list you will ever see, in apps, pamphlets and baby books, was written for babies born around their due date. A baby born 8 weeks early has had 8 fewer weeks to work with. Reading the standard list against their birth date asks them to be somewhere they have not had time to reach. The fix is one subtraction, and it is the same one your pediatrician uses.

First, the math

Take your baby’s actual age in weeks, counted from the day they were born. Subtract the number of weeks they arrived early. What is left is the adjusted age (doctors also call it corrected age), and that is the age you look up on any milestone list. The AAP applies this to babies born more than 3 weeks early (AAP: Your Preemie’s Growth and Developmental Milestones).

The AAP’s own worked examples make it concrete. A baby who is 8 weeks old and was born 3 weeks early has an adjusted age of 5 weeks. A 16-week-old born 4 weeks early is 12 weeks adjusted, so you read the 3-month list. A 24-week-old born 5 weeks early is 19 weeks adjusted. One detail worth knowing: the AAP counts a month as 4 weeks in these tables, so “3 months” means 12 weeks.

If you would rather not do the subtraction at 3 a.m., our forecast does it for you: give it the birth date and the due date, and every window it shows runs on the adjusted clock. The full reasoning behind adjusted age is in our guide to corrected age.

The milestones, month by month

The examples below are drawn from the AAP’s preemie milestone list. Each age is the adjusted age. These are samples of typical development, not a complete list and not a test your baby sits.

Around 1 month adjusted

  • Holds their chin up when on their tummy
  • Watches your face and follows you with their eyes
  • Makes brief little vowel sounds
  • Calms when picked up or spoken to

Around 2 months adjusted

  • Smiles back at you
  • Makes short cooing sounds
  • Lifts head and chest on their tummy
  • Keeps their head steady when held in a sitting position

Around 4 months adjusted

  • Laughs out loud
  • Makes long cooing sounds and turns to voices
  • Rolls from tummy to back
  • Grasps objects and plays with their fingers

Around 6 months adjusted

  • Sits briefly without support
  • Rolls from back to tummy
  • Babbles sounds like “da”, “ba”, “ga”
  • Passes a toy from one hand to the other and looks when their name is called

Around 9 months adjusted

  • Sits well and crawls on hands and knees
  • Pulls up to stand
  • Waves bye-bye or holds out arms to be picked up
  • Plays peekaboo and says “dada” or “mama” to anyone

Around 12 months adjusted

  • Takes first steps and stands without support
  • Says “mama” or “dada” for the right person, plus one other word
  • Picks up small pieces of food with finger and thumb
  • Follows simple directions that come with a gesture

Two honest notes. First, these describe what typically happens, and typical is a range, not a date. Second, the order matters more than the calendar: babies babble before words, pull up before standing, stand before walking. Watching your baby move through the sequence tells you more than any single deadline.

What the doctor is actually watching

At each well-child visit, the doctor checks progress and asks what you are seeing at home. The visits happen on the regular calendar, but the development conversation should run on adjusted age. If nobody says the words, say them yourself: “What does this look like for her adjusted age?” is a complete and reasonable question.

Pediatricians also have a playbook for exactly this. In 2023 the AAP published a clinical framework for how primary care doctors should monitor children born preterm through their early years (AAP Pediatrics, 2023). Follow-up appointments, developmental screenings and referrals are part of the standard route for preemies, not a sign that anyone is worried about your child in particular.

One phrase worth asking about by name: early intervention. These are programs that give some babies extra help with their development, and the AAP suggests parents simply ask their baby’s doctor about them. Starting early intervention is support, not a diagnosis, and using it does not mean your baby is off course.

Until when, and what catching up looks like

Adjusted age is not forever. The AAP uses it when tracking development until age 2, and notes that by then most children born early have caught up to the typical milestone range. If your child has not caught up by 2, the AAP’s own framing is worth holding onto: they may need extra support for a longer period. That is a plan, not a verdict.

Bliss, the UK charity for babies born premature or sick, gives parents the same starting point: measure development from the due date, and expect your baby to reach things a little later than a friend’s full-term baby of the same birth age (Bliss: Early developmental milestones). The comparison with the baby group will sting less once you know which calendar your baby is actually on.

When to call your pediatrician

Talk with your doctor

Check milestones against the adjusted age, then use the standard rule: if your baby is missing one or more milestones at that age, or has lost a skill they once had, bring it to the doctor and ask about developmental screening. Preemies usually have follow-up visits already scheduled, so use them fully and bring your questions written down. And your own concern is reason enough to call.

Keep reading

Sources

*Peanutbean provides general information for educational purposes only. It is n

Common questions

What milestones should my premature baby be reaching?

The same ones as any baby, checked at the adjusted age. Take your baby's age in weeks, subtract the weeks they were born early, and read the milestone list for that adjusted age. The American Academy of Pediatrics recommends doing this until age 2.

How long do preemies use adjusted age for milestones?

Until about age 2. The AAP notes that most children born early have caught up to the typical milestone range by then. If your child has not, it does not mean something is wrong, but they may need extra support for longer, so talk with your doctor.

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Peanutbean provides general information for educational purposes only. It is not medical advice. Every baby develops at their own pace. Always talk to your pediatrician about your child's health.