Milestones Are Based on Due Date — Not Age. Here’s Why That Matters.
If you’ve ever found yourself Googling “when should my baby roll over,” “when do babies sit up,” or “is my baby behind?” at 2 a.m. — same, mama.
I’ve been there, anxiously scrolling through forums, comparing my sweet boy to someone else’s on Instagram and wondering if I was doing something wrong.
But here’s something I wish every new mom was told right away:
Most baby milestones are measured from your baby’s due date — not their actual birth date.
Wait… What?
Yep. Whether your baby arrived early, right on time, or fashionably late, most pediatricians and child development experts go by adjusted age, not chronological age, when it comes to early milestones.
So if your baby was born a few weeks early (which is so common!), their little body and brain are still playing catch-up — and that’s completely normal.
Here’s a Quick Example:
Let’s say your baby was born 3 weeks early.
If they’re 4 months old on the calendar, their adjusted age is really closer to 3 months when it comes to things like:
Holding their head up
Rolling over
Grabbing toys
Sitting with support
Babbling or cooing
And that’s the timeline your pediatrician will usually go by — especially in the first year.
What the Experts Say
The American Academy of Pediatrics and CDC both recognize adjusted age (also called “corrected age”) as the standard for tracking developmental progress in preterm and early babies — usually until age 2.
So unless your pediatrician has expressed a specific concern, your baby taking an extra few weeks to hit certain milestones is not something to stress over.
Why This Reframe Matters for Moms
Because it removes some of the pressure.
Because your baby is doing beautifully — at their own pace.
Because comparison steals the joy out of motherhood faster than a skipped nap.
And because once I realized this, I stopped asking, “Why isn’t he doing that yet?”
And started asking, “How can I support him where he is right now?”
Gentle Reminders:
Your baby isn’t “behind.” They’re just on their own timeline.
Milestones aren’t competitions — they’re guides.
There’s a wide, healthy range of normal.
You’re doing a great job — even if your baby doesn’t sit up exactly at 6 months.
What Helped Me Worry Less:
Talking to our pediatrician (instead of Google)
Keeping a list of the progress I did see
Following accounts that showed realistic development — not just the early achievers
Repeating this to myself:
“There’s no prize for rolling over first.”
Final Thought
So if your baby isn’t rolling, sitting, crawling, or clapping right “on schedule,” please hear this:
You are not doing anything wrong.
Your baby is not behind.
They’re just taking their sweet time — and that’s okay.
Trust their pace.
Trust yourself.
And celebrate every tiny milestone… whenever it comes.
