Learning to sit on her own gives your baby a new perspective on her world. Once her back and neck muscles are strong enough to hold her upright and she’s figured out where to put her legs so she won’t topple over, it’s just a matter of time until she moves on to crawling, standing, and walking.
When it develops
Most babies start to learn to sit independently at about the same time they’re manage rolling over and holding their head up. The muscles they need to use develop gradually from birth, finally getting strong enough sometime between four and seven months. By the time they’re eight months old, 90 per cent of babies can sit well without support.
How it develops
While you can prop your baby in a sitting position almost from day one, true independent sitting doesn’t begin until your baby has head control. Starting at about four months, your baby’s neck and head muscles strengthen rapidly, and she’ll learn to raise and hold her head up while she’s lying on her stomach.
Next she’ll figure out how to prop herself up on her arms and hold her chest off the ground, like a mini-pushup. By five months she may be able to sit momentarily without assistance, though you should stay nearby to provide support and surround her with pillows to cushion a possible fall.
Soon she’ll figure out how to maintain her balance while seated by leaning forward on one or both arms, and by seven months she’ll probably be able to sit unsupported (which will free her hands for exploring), and she’ll learn how to turn when sitting to reach a desired object. At this point she may even be able to get into a sitting position from lying on her stomach by pushing up on her arms. By the time she’s eight months old, she’ll likely be sitting well without support.
Once she figures out that she can lunge forward from a sitting position and balance on her hands and knees, your baby will be almost ready to crawl, a skill most children master completely by the time they’re a year old. She may get the hang of moving forward (or backward) on all fours as early as six or seven months old; once she does, she’ll be very mobile and very curious, so get your childproofing done well in advance.
Most paediatricians also recommend waiting until your baby is sitting with minimal support before starting her on solid foods.
You can help your baby get ready to sit by encouraging her to play face-down on the floor and then prompting her to look up. Lifting her head and chest to see toys or your face helps strengthen her neck muscles and develops the head control necessary for sitting up. Using a bright toy or one that makes noise is a good way to also make sure her hearing and vision are on the right track. Once your baby can sit fairly well, put toys and other intriguing objects just out of her reach — they’ll hold her attention as she learns to balance herself with her arms.
As always, and especially when she’s just learning to sit, be sure to stay close to your baby in case she falls — or wants to show off her new skill.
When to be concerned
If your baby isn’t able to hold her head up steadily by the time she’s about six months old and hasn’t started learning to prop herself up on her arms, bring it up the next time you talk to your doctor or health visitor. Babies develop skills differently, some more quickly than others, but head control is essential to sitting independently, and sitting is key to crawling, standing, and learning to walk. Keep in mind that premature babies may reach this and other milestones later than their peers.