Week-by-week library · about 4.5 to 5 months old
Week 20
Quick answer
What is my baby up to at about 4.5 to 5 months old?
This week, sitting with a little help is starting to feel steady.
What's developing
Motor
With support at the hips or a few pillows around, many babies can sit for short stretches now, even though independent sitting is still a bit further out for most.
Social
Babies this age often watch faces closely, picking up on tone and expression even before they understand words.
Try this together this week
- Supported sitting sessions on the floor, surrounded by soft support, for a new view of the world.
- Name emotions out loud as you make expressions ("happy face!", "surprised face!"); the face-watching habit is a real learning window.
- Offer a variety of safe toys with different sounds and textures during floor play.
- Keep tummy time in the mix even as sitting practice ramps up; both build different muscle groups.
What parents often notice
A lot of families start solid foods somewhere in this general window based on their pediatrician's guidance; readiness and timing are worth discussing directly with your baby's doctor rather than a website.
Sourced to
- American Academy of Pediatrics, HealthyChildren.org
Last reviewed by the This Week Baby editorial team.