It's not hard to impress new parents. Because babies are born helpless and dependent on us for everything, it's always exciting to see them learn how to do anything for themselves. From learning how to grasp one's finger, to discovering how to crawl, to eventually mastering potty training - there are many development achievements we parents take pride in. 

One milestone that's always worth celebrating is when baby learns to roll over. Michelle Macias, MD, a professor of pediatrics and the director of the developmental-behavioral pediatrics fellowship program at the Medical University of South Carolina, says it's an essential first step for baby to learn how to sit up, crawl and eventually start walking. 

Though the timeline of when rolling over begins is different from baby to baby, there are always signs parents can look out for. 

When do babies roll over?

The Centers for Disease Control and Prevention notes that by the time baby is 6 months old, he or she has usually met developmental milestones like being able to easily recognize familiar people, interacting with others through laughs and sounds, reaching for the toy they want, and being able to roll over. Jason Nagata, MD, a pediatrician at UCSF Benioff Children’s Hospital in San Francisco, explains that some infants start rolling over as early as 3-4 months and some do so later than 6 months. "Timing can vary," he says. 

Rolling over is also a process baby doesn't master overnight as they will usually learn to roll from their back to side first, then from tummy to back, and finally from their back to tummy as they realize they have full range of control, says Bonnie McBride, PhD, an associate professor of developmental and behavioral pediatrics at The University of Oklahoma Health Sciences Center.

In addition to being a precursor for the aforementioned physical milestones of crawling and walking, rolling over also helps baby build core strength needed for head and body control and usually means better sleep for baby once they get used to their new ability and freedom. "Rolling can lead to temporary disruptions in an infant’s sleep as they are more mobile and may wake up more frequently," explains Nagata. "However, infants soon experience improved sleep because they are able to find a more comfortable position on their own." 

What are the first signs of rolling? 

Among the earliest signs baby might be close to rolling over is if they turn their head to keep track of mom or dad or an object or if they reach around their body to find a toy or comfort item. McBride says babies may start pushing up on their arms from their tummy or start shifting their body weight around as other early signs.  

"Infants also start lifting their head and shoulders more during tummy time, roll onto their shoulders or side, and kick or twist their legs," adds Nagata.

How to prepare for baby rolling over? 

When parents see such signs, they should "provide safe places for baby to explore with toys and people to interact with," suggests McBride. Placing items above their heads or just out of reach on the floor can also encourage exploration and rolling so long as baby knows they are there. 

Once baby reaches 4-6 months and shows signs of rolling, parents can also start guiding them through the process of rolling over by practicing the motion from both sides and helping them feel through the movement. Remember, "never leave (babies) unattended on a changing table, bed or other furniture and always be aware and alert," advises McBride. "They can move fast and even looking or turning away for a few seconds is not recommended."

When do babies start crawling?There's no hard and fast rule but here's when to be worried.