My baby was born early. When should they reach milestones?

The short answer

Count from the due date, not the birthday.

For babies born early, doctors use corrected age: your baby’s age from their birthday, minus the weeks they were born early. A 6-month-old who was born 2 months early is expected to do what a 4-month-old does. Doctors use corrected age for milestones for the first 2 to 3 years.

What to do next

Keep every follow-up visit. Many NICU graduates have extra checks for development, hearing and eyes. These visits catch problems early, when help works best.

Ask about early intervention. In Louisiana, the program for babies and toddlers from birth to age 3 is called EarlySteps. You can ask for an evaluation yourself; you do not need to wait for a doctor’s referral.

Track milestones by corrected age. Use the list below. Bring notes and short videos of what worries you to the next visit.

Why babies born early may need extra help

A baby's brain grows quickly in the last weeks before the due date. Babies born early do that growing outside the womb, often while they are sick. That is why they have a higher chance of delays in movement, language and learning.

Most babies born early do well. Watching closely, and getting help early when it is needed, gives every baby the best start.

Does early intervention help?

Yes. A large review of 44 studies with more than 5,000 babies born early found that programs that start in the first year help thinking and learning skills in babies and preschoolers, and movement skills in babies. Source 2

Early intervention usually happens at home or in childcare. Therapists, such as physical, occupational and speech therapists, show you ways to build skills during everyday play, feeding and bath time.

Milestones to watch, by corrected age

Most children can do these by the age shown. Use your baby's corrected age. Source 3

2 months: Smiles when you talk to or smile at them; holds head up when on tummy
4 months: Holds head steady when you hold them; makes cooing sounds like "oooo" and "aahh"
6 months: Rolls from tummy to back; laughs
9 months: Sits without support; makes sounds like "mamamama" and "babababa"
12 months: Pulls up to stand; waves "bye-bye"
15 months: Takes a few steps on their own
18 months: Walks without holding on; tries to say three or more words besides "mama" or "dada"
2 years: Says at least two words together, like "more milk"; kicks a ball

If your baby is not doing something on the list by their corrected age, it does not always mean there is a problem. It does mean it is time to talk with the doctor.

When to call the doctor or 911

Call 911 now if

Your baby has trouble breathing, or their lips or skin turn blue or gray.
Your baby has a seizure: stiffening, jerking, or staring spells with no response.
Your baby is very hard to wake up, or is limp.

Call your child's doctor if

Your baby loses a skill they used to have. This is always worth a call.
Your baby is not reaching milestones for their corrected age.
Your baby seems very stiff or very floppy, or uses one side of the body much more than the other.
Your baby does not react to loud sounds or does not look at faces.
Feeding is hard, or your baby is not gaining weight.
You are worried. You know your baby best.

References

Engle WA; American Academy of Pediatrics Committee on Fetus and Newborn. Age terminology during the perinatal period. Pediatrics. 2004;114(5):1362-1364. PubMed 15520122 doi:10.1542/peds.2004-1915

Orton J, Doyle LW, Tripathi T, et al. Early developmental intervention programmes provided post hospital discharge to prevent motor and cognitive impairment in preterm infants. Cochrane Database Syst Rev. 2024;2(2):CD005495. PubMed 38348930 doi:10.1002/14651858.CD005495.pub5

Zubler JM, Wiggins LD, Macias MM, et al. Evidence-informed milestones for developmental surveillance tools. Pediatrics. 2022;149(3):e2021052138. Milestone checklists: CDC Learn the Signs. Act Early. PubMed 35132439 doi:10.1542/peds.2021-052138 CDC milestones