Specs, warning lights, a maintenance schedule, and troubleshooting — grounded in WHO growth standards, AAP guidance, and real developmental science, tracked day by day from the moment you started counting.
Enter your dates once. Everything below — age, corrected age, the maintenance schedule, the growth chart — updates itself. Built for both parents: whoever opens this page sees the same dashboard. Nothing is sent anywhere; your dates are saved only in this browser.
Day 1 is the day you started counting. Everything else is computed from here.
Every car manual opens with a specs page: engine size, weight class, trim level. Your baby's two specs are gestational age at birth (how many weeks of pregnancy were completed) and birth weight. Together they determine which chapter of this manual matters most right now.
| Classification | Gestational Age | What It Usually Means |
|---|---|---|
| Late preterm | 34 wks 0 days – 36 wks 6 days | The most common preterm group. Often a short NICU stay or none at all; feeding and temperature regulation are the main watch-items. |
| Moderately preterm | 32 wks 0 days – 33 wks 6 days | Usually a NICU stay of several weeks. Feeding and breathing support are common. |
| Very preterm | 28 wks 0 days – 31 wks 6 days | Longer NICU course. Higher chance of respiratory support, ROP screening, and feeding tubes. |
| Extremely preterm | Under 28 weeks | The most intensive NICU care. Every week in the womb after this point measurably changes the odds — your NICU team will walk you through it week by week. |
Birth weight has its own classification, tracked alongside gestational age: low birth weight (under 2,500 g), very low birth weight (under 1,500 g), and extremely low birth weight (under 1,000 g). A baby can be preterm without being low birth weight, and vice versa — your NICU team reads both specs together.
A car's odometer reads actual miles driven, not miles since it left the factory floor. Your preemie has two odometers, and mixing them up is the single most common source of new-parent panic.
Chronological age is simple: days since birth. It's what goes on forms, and it's what determines the vaccine schedule — vaccines are given by chronological age, regardless of prematurity, per AAP guidance.
Corrected age (also called adjusted age) is chronological age minus the number of weeks born early. It's the number that matters for growth curves and developmental milestones, until your child is about 2 years old (some extremely preterm children are corrected up to age 3, per your specialist's guidance).
Formula: Corrected age = Chronological age − (40 weeks − gestational age at birth). A baby born at 32 weeks is 8 weeks "early" — at 12 weeks chronological age, she is 4 weeks corrected age. Rolling over at 4 months corrected age (not chronological) is on schedule, not late.
This manual's planner above does this math for you, every time you open it.
Two tiers, like a car's dashboard: the light that means pull over now, and the light that means call the shop this week. Preemies carry real added risk in the first year, especially for respiratory illness (RSV) and apnea — take both tiers seriously.
When in doubt, call. NICU graduates are followed closely for a reason — your team would always rather hear from you than not.
The planner above builds your personal schedule from your dates. Here's the reference version it's built from:
| Check | Typical Timing | Why |
|---|---|---|
| Hearing screen | Before NICU discharge | Standard for all newborns; repeated if the first pass is inconclusive. |
| ROP (eye) exam | 4–7 weeks chronological age | Required if born ≤30 weeks gestation or birth weight <1,500g; screens for retinopathy of prematurity. Follow-up ophthalmology visit 4–6 months after discharge. |
| First pediatrician visit | 2–3 days after discharge | Weight check, feeding review, jaundice check. |
| Vaccines | By chronological age, per the standard CDC/AAP schedule | Prematurity does not delay vaccines — this is the one schedule that runs on chronological, not corrected, age. |
| Well-child checks | ~1, 2, 4, 6, 9, 12 months corrected age | Growth curve, developmental screening, milestone check-ins. |
| RSV prevention | Discuss timing with your pediatrician each fall/winter season | High-risk preemies may qualify for RSV-preventive treatment; ask before RSV season starts. |
This is a general reference, not a prescription. Your NICU discharge team will give you a specific schedule for your baby — follow theirs over this one.
Reflux / spit-up: Very common in preemies due to an immature valve at the top of the stomach. Usually improves with age. Keep baby upright 20–30 minutes after feeds; mention forceful ("projectile") vomiting or poor weight gain to your pediatrician.
Apnea of prematurity: Brief breathing pauses are common before term-equivalent age and usually resolve by then. If your baby went home on an apnea monitor, know your device's alarm patterns and your rescue steps cold before you need them.
Slow weight gain: Preemies often "cross percentiles" upward in the first year as they catch up — a temporarily low percentile on the growth chart, by itself, is not alarming. A flattening or downward-crossing trend over several checkups is what your pediatrician will want to look at.
Sleep: Corrected age, not chronological age, predicts sleep organization. Follow safe-sleep guidance (back to sleep, firm flat surface, nothing loose in the crib) at chronological age from day one — safe sleep practices are not adjusted for prematurity.
Some NICU graduates come home with actual machines, and those machines have their own actual manuals — filter change intervals, alarm meanings, cleaning schedules. If your baby doesn't need any of this, skip the chapter. If your baby does, this is the part of "like a car manual" that isn't a metaphor.
| Equipment | Routine Maintenance | Know Before You Need It |
|---|---|---|
| Portable oxygen concentrator (e.g. SeQual / CAIRE Eclipse) | Inspect the air-inlet filter daily; wash it with warm water and mild detergent about once a week, rinse, and let it air-dry completely before reinstalling — never run the machine without the filter, and never put a wet filter back in. Replace the filter annually. Keep a dry spare filter on hand so the machine keeps running while the other one dries. | Where the spare filter and backup battery live. What the alarm tones mean. Who to call (equipment supplier, not 911) for a machine fault vs. who to call for your baby's symptoms. |
| Apnea / cardiorespiratory monitor | Check the chest belt/sensor placement at every use; keep leads clean and untangled; charge or replace batteries per your unit's schedule. | Your NICU team reviews this with you before discharge — know your specific alarm patterns and rescue steps cold. A monitor alarm is a prompt to check your baby first, the device second. |
| Feeding pump | Follow your supplier's cleaning schedule for tubing and bags; inspect for kinks or air in the line before each feed. | What a normal flow rate/sound is for your setup, so you notice quickly when something's off. |
Your home equipment supplier and NICU discharge team train you on your specific machine before you leave — this table is a memory-jogger, not a replacement for that training or for the manufacturer's manual.
A car manual doesn't have a driver's edition and a passenger's edition. This one doesn't either. Corrected age, warning signs, and the maintenance schedule are the same facts whoever is holding the baby at 3 a.m.
Your recovery is its own maintenance schedule — postpartum checkups matter too, especially after a preterm delivery. Tracking your baby's numbers doesn't require you to also be the only one tracking them.
Track dates from Day 21, not from the day you first held your baby. Know the corrected age math, know the red-light symptoms, and take a shift on the maintenance schedule. Precision is a form of care that doesn't require a uterus.
"Day by Day" starts counting from an estimated date of conception (Day 1), which runs about two weeks behind the "pregnancy week" number your due date is based on (that one counts from your last menstrual period). Both numbers describe the same baby; the planner above shows you both.
Growth percentiles: WHO Child Growth Standards (weight-, length-, and head-circumference-for-age, LMS reference tables) · Corrected age & developmental guidance: HealthyChildren.org (AAP) · Preterm classification: March of Dimes PeriStats · ROP screening: AAP Screening Examination of Premature Infants for ROP · NICU discharge & follow-up: AAP Hospital Discharge of the High-Risk Neonate · Embryology: UNSW Embryology / Carnegie Stages · Apnea & RSV warning signs: Kaiser Permanente, Cleveland Clinic · Oxygen concentrator & home equipment: Portable Oxygen Concentrator Maintenance Guide, March of Dimes: Common NICU Equipment