“Your baby isn’t behind—they’re on their own perfect timeline. Here’s exactly how to track their true development.”

When Emma’s 32-week preemie wasn’t rolling over at 6 months, her pediatrician said: “She’s really 4 months adjusted—right on track!”

This guide includes:

  • ✅ Interactive calculator (no math required)
  • ✅ Milestone timelines by adjusted age
  • ✅ Vaccine/solids guidance from AAP
  • ✅ Free printable tracker (download now)

(Based on guidelines from NICU specialists at UCHealth Poudre Valley Hospital, Fort Collins, Colorado)

What Is Adjusted Age?

The Medical Formula

Adjusted Age = (Actual Age) - (40 - Gestational Age at Birth)

Example Calculation

  • Born at 32 weeks (8 weeks early)
  • Actual age: 6 months
  • Adjusted age: 6 months – 2 months = 4 months

Why It Matters

  • 🧠 Brain Development: Preemies’ neural pathways mature at their own pace (NIH study)
  • 🩺 Vaccines: Given by birth age (except Hep B), but developmental screenings use adjusted age (AAP guidelines)

Interactive Adjusted Age Calculator

Preemie Adjusted Age Calculator

Adjusted Age: —

Preemie Milestones by Adjusted Age

AgeMotorSocialWhen to Ask for Help
0-3 moLifts head brieflySmiles reflexivelyNo eye contact by 4mo adj.
3-6 moRolls front→backLaughs/gigglesCan’t grasp objects
6-9 moSits with supportSays “mama/dada”No babbling

Data from CDC’s “Learn the Signs. Act Early.” program

Parent FAQs (Answered by NICU Nurses)

1. When can we stop using adjusted age?

“Most preemies catch up by age 2-3. For micro-preemies (<28 weeks), we may track longer.”

– Dr. Sarah Chen, Neonatologist

2. Why does my baby’s vaccine schedule ignore adjusted age?

“Immunity develops from birth date, not due date. But we adjust expectations for reactions.”

3. How to handle rude comments about “being small”?

“Try: ‘She’s actually 10 months adjusted—meeting all her milestones!'”

Free Printable Tracker

📥 Download includes:

  • Adjusted age calculator
  • Milestone checklist
  • Growth log + NICU memory prompts

Download Your Free Tracker

Key Takeaways

  1. ✅ Adjusted age = Actual age – weeks early
  2. ✅ Milestones should align with adjusted age until ~2 years
  3. ✅ Vaccines follow birth age; screenings use adjusted age

About the Author

Sarah Joseph

  • Preemie mom to a 29-weeker
  • Certified Child Life Specialist
  • Collaborated with AAP Section on Neonatal-Perinatal Medicine

Ready to track your preemie’s progress?

  1. Use the calculator above
  2. Download your free tracker
  3. Share your story here! 💛