According to the American Academy of Pediatrics, babies should be able to roll over in both directions by the age of 7 months. Rolling over in both directions means from tummy to back and then from back to tummy. However, there is a range as to when this may happen. Some babies can roll over, at least on one side, by the time they are 4 months old.
Before Rolling Over
There are several muscle groups and maneuvers children need to develop before they can roll over. Before your infant can roll over, you may notice he practices what looks like a swimming position when on his belly. This is when he lifts his head and arms off the floor at the same time and wiggles. You may see this happen at about 5 months of age, according to “Caring for Your Baby and Young Child.” This maneuver helps build stomach and arm muscles needed for rolling over.
For infants to learn to roll over, they have to have time on the floor to practice using their muscles. "Tummy time," where you place your infant on his tummy for short periods of time, can greatly help build these muscles and allow him to practice the "swimming" motion. It is also easier for infants to start rolling over from a tummy position, as they can use their arms and legs to get a good push, so the first rollover is often from tummy to back, rather than from back to tummy.
When to be Concerned
According to the AAP, infants should be able to roll over in at least one direction, either tummy to back or back to tummy, by 5 months of age. By the age of 7 months, infants should be rolling in both directions on their own without help. If your infant hasn't met these milestones, you may want to talk to your pediatrician about it.
As parents, you have many more milestones to look forward to after your child has rolled over. Now is when your little one is starting to become mobile, and it will soon be time to babyproof the house. Rolling over leads to scooting on the belly and then crawling. A few months after rolling over, your baby will be pulling herself up to a standing position using nearby furniture or people.