On average, babies begin sitting up at around 6 to 8 months of age, says Michelle Baboun, a pediatric physical therapist in Florida. At about 6 months old, most babies can sit, using their arms propped in front of them for support. Some can sit erect without using their arms for support, but if your baby is this bold, expect loss of balance and falls to be frequent, especially with movements of the head and reaching.
"By about 6 months, babies can usually sit alone for around 30 seconds," says Maribeth Gorman, a senior occupational therapist at Children's Memorial Hospital in Chicago. "By 7 months, they are pretty steady and can begin using their hands to play in front of them while they sit."
"As babies get closer to 8 months, most have the trunk and pelvic strength to maintain unsupported sitting, can reach and move in sitting, and are able to make adjustments for losses of balance," Baboun says. (If your baby was a preemie, be sure to use adjusted age.)
"Babies begin practicing the moves that will lead to sitting during the newborn period," says Gorman. The ability to sit begins with the ability to control one's own head, a skill your child is building as he sits with support on your lap or has tummy time with you on the floor. Gradually, he requires less and less support. By 4 or 5 months, many babies are just barely sitting, able to stay in a propped position for a few seconds.
And using hands—whether to play with toys on a mat on the floor or to paint with mashed bananas in a
high chair—is a big deal for your baby. "Remember, it is the use of our hands that has given us an advantage over other species (combined, of course, with our cognitive abilities)," says Dr. Charles Shubin, pediatrician and director of pediatrics for Mercy Medical Center Family Care in Baltimore. The ability to manipulate objects in front of her is an important next step in your child's development.
Susie Alessi's son was also around 6 months when he began to sit up by himself. "We did tummy time and 'baby pushups' where I would lay him across my legs and make him lift up or push up off of the floor with his hands," she says.
That kind of practice is very important in helping babies reach milestones like sitting. "The most important thing is to start out with plenty of time for play on the floor rather than in a swing or bouncy seat," Baboun says. "Supervised tummy time is so important for the development of head control, arm strength, and trunk strength."
What about the array of baby gear designed to help with sitting up? You don't really need all the equipment, Gorman says. Instead, what your baby needs is opportunity. "Babies are motivated to sit—they want to do it. Your baby doesn't always need to be cuddled against you while sitting on your lap. Allow him to sit farther out, closer to your knees, and let him practice holding his head up. Get down on the floor and play with him, and let him practice sitting with your support."
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Babies don't always follow an exact timetable. However, if you have concerns about your baby's development, don't hesitate to bring those concerns to your child's healthcare provider, Dr. Shubin says. Your doctor will evaluate your baby's developmental progress, and also look for any possible neuromuscular problems.