What is tummy time and why is it important to your infant's development? Our experts weigh in.During tummy time, your baby lays on her belly to play while you supervise. Since your baby sleeps on her back to help prevent sudden infant death syndrome (SIDS), she needs to spend some of her awake time on her stomach to develop physically and mentally. The BenefitsOn her tummy, your baby lifts her head, which strengthens her neck and upper back muscles.Being able to move her head reduces your baby’s risk of SIDS because she can move away from anything smothering her. Strong muscles let your baby roll over, sit, and crawl.Tummy time also gives your little one a different view of the world.Babies need to learn how to support their heads when they are still, says Tanya Altmann, MD, a pediatrician in California. “They also need to be able to turn their head in response to what's happening around them and hold their heads steady when they're moved."Spending time on her stomach also helps your baby's head become round instead of developing flat spots on the back of her head.When to startTummy time can begin right after birth, says Chris Tolcher, MD, FAAP, a pediatrician in California, or definitely by the time your baby is a month old.For the first few weeks, you may want to delay tummy time until her umbilical cord stump falls off. As long as your baby is comfortable, though, you can safely let her play on her stomach right away.You may be surprised to see that “even a newborn can start to turn [her] head side to side," says Laura Jana, MD, a Nebraska pediatrician.Remember: Never let your baby sleep on her tummy, because even one time increases her risk of SIDS. When you put your baby on her tummy, always place her on a smooth, flat surface with no loose items (toys, blankets, pillows) close to her, which might block her airway, Tolcher says. How Frequently and for How LongSome pediatricians suggest having your baby play on her stomach five or 10 minutes a couple times a day. Others say you don't have to worry about a set amount of time. There’s no set guideline."I usually recommend starting to offer tummy time at least once per day," says Scott Cohen, MD, FAAP, an attending pediatrician at Cedars Sinai Medical Center. He suggests leaving your baby on her tummy as long as she accepts it -- whether that’s 15 seconds or 15 minutes.It's time to pick your baby up if she starts crying or fussing.Some babies initially resist tummy time because they don't have good control and find it hard to lift their heads. But the more practice your baby gets, the better she’ll like it, says Cohen, who is also the author of Eat, Sleep, Poop.How to make tummy time funTurning tummy time into playtime is as easy as lying on your belly and facing your baby, Jana says.Baby experts and parents offer these tips for making your baby's tummy workout fun:When your baby can't support her own head yet, put her on your chest tummy down. Or put her across your lap on her stomach for burping. Get on the floor with your baby. "Make faces, talk to them, get a tummy time mat, and hold colorful toys or a rattle in front of them." Cohen says. Encourage your baby to look up by talking or singing above her head. Place your baby next to a mirror or musical box -- or something else she’ll want to reach for. Place your baby's upper body and arms over a nursing pillow. This elevation gives a nice view and may be more comfortable. If your baby starts to fuss, divert her attention. Turn her on her back, then blow "raspberries" on her tummy. Flip her onto her stomach and make the same raucous noises on her back. That’s distraction at its silly best. Some parents suggest waiting an hour after your baby eats to start tummy time, for the baby's comfort and for mom and dad -- less spit up to clean up!Tummy time trouble makersSome babies have strong opinions about being on their stomachs. After all, tummy time is hard work!"I let parents know that just because an infant 'squawks' when on [her] belly, it doesn't always mean [she doesn’t] like it," Jana says. "For some, being put on their belly causes them to try to scoot -- an effort that is often accompanied by exertional squawking."What if your baby is just plain angry about tummy time?"Keep trying," Cohen says. "The more exposure and practice the better.” As her head and neck get stronger, she’ll enjoy it more.Every baby meets each milestone when she’s ready, so don't worry if yours isn't a fan of tummy time right away. Ask your baby's pediatrician your questions. In the meantime, don't be shy about trying to make tummy time "a fun part of every day," Altmann says.