Remember that night you survived on 2 hours of sleep while trying to Google “is my baby normal” at 3 AM? Yeah, we’ve all been there.
The 3-6 month stage is wild – one week they’re barely lifting their head, the next they’re trying to eat their toes. Every baby hits baby growth and development milestones differently, and that’s completely fine.
I’ve helped thousands of new moms navigate this chaotic, beautiful period, and I’m about to save you from the late-night panic scrolling. By the end of this post, you’ll know exactly which milestones matter, which ones don’t, and the simple things you can do right now to support your little one’s development.
But first, let me tell you about the surprising connection between tummy time and your baby’s future athletic abilities…
Physical Growth Milestones (3-6 Months)
Weight Gain Patterns & What’s Normal
Watching your little one grow is one of the most exciting parts of these early months! Between 3 and 6 months, most babies gain about 1-2 pounds per month. Your baby might’ve doubled their birth weight by around 5 months – that’s some serious growing!
But here’s the thing: every baby follows their own unique pattern. Some babies pack on pounds quickly, while others take a more gradual approach. My friend’s daughter was in the 90th percentile by month 4, while my son barely hit the 30th percentile – both perfectly healthy!
After that initial newborn weight loss, your baby should be steadily gaining. If your little one was born on the smaller side, they might gain weight more quickly now as they “catch up.” Breastfed babies often gain weight a bit differently than formula-fed babies – sometimes a little slower after the first 3 months, which is totally fine.
Height & Head Circumference Development
Your baby will typically grow about an inch per month during this period. Again, consistency matters more than the exact numbers.
Head growth is particularly important as it reflects brain development. Your pediatrician will measure your baby’s head circumference at each visit. Most babies’ heads grow about 0.5 inches per month during this time.
Funny enough, head growth often happens in spurts – you might notice your baby’s favorite hat suddenly doesn’t fit anymore!
Tracking Your Baby’s Growth Charts
Your pediatrician uses growth charts to track three key measurements:
- Weight
- Length
- Head circumference
These charts show percentiles, which compare your baby to other babies of the same age and sex. Being in the 50th percentile means 50% of babies are smaller and 50% are larger.
What really matters isn’t the specific percentile but consistency in your baby’s growth curve. A baby who’s been in the 15th percentile since birth and stays there is perfectly healthy! What doctors watch for is any sudden changes across percentile lines.
I recommend downloading a baby growth tracking app – they’re super helpful for visualizing your baby’s progress between doctor visits.
When to Consult Your Pediatrician
Most growth variations are completely normal, but sometimes you should check in with your doctor. Call your pediatrician if:
- Your baby isn’t gaining weight or is losing weight
- There’s a dramatic drop across two or more percentile lines on the growth chart
- Your baby’s head size is growing much faster or slower than expected
- You notice a flattening on one side of your baby’s head
- Your baby seems unusually hungry all the time despite regular feeding
Trust your gut! You know your baby better than anyone. Most growth concerns turn out to be nothing to worry about, but it’s always better to ask your doctor than to wonder and worry.