Swaddling, the SNOO, and What They Mean for Your Baby’s Development

Swaddled Baby with Headband

Swaddling a newborn can feel like one of the few things that actually work in those early days. Wrap them up snugly, and suddenly your fussy baby settles into sleep, just like that. It’s no wonder swaddling has been a time-honored tradition across cultures for centuries. And in today’s world of high tech parenting, the SNOO Smart Sleeper has taken swaddling to a new level—offering an automatic rocking bassinet that promises better rest for everyone.

The appeal is real: calmer babies, longer naps, maybe even the chance to take a shower. But as a physical therapist and a mom who knows how desperate we can feel for sleep, I also want to gently pull back the curtain and talk about the other side—how swaddling (and devices like the SNOO) affect your baby’s development, especially when it comes to motor skills and reflex integration.

Swaddling works because it recreates the feeling of the womb. It quiets the nervous system, softens the jolt of the startle reflex, and gives babies a sense of security. The SNOO builds on this by adding motion and white noise, rocking your baby gently when they stir, and keeping them safely on their backs. For families navigating the fog of the fourth trimester, these features can feel like a lifeline.

But for all its benefits, swaddling also restricts movement. And for a baby, movement isn’t just nice to have—it’s essential. From day one, babies are learning about their bodies by stretching, wiggling, kicking, and shifting. These tiny movements lay the foundation for bigger milestones like rolling, crawling, and walking. When a baby is swaddled for long periods—especially during the day or beyond those early months—they miss out on opportunities to strengthen muscles, explore their environment, and integrate reflexes in a natural way.

This is where the conversation about the SNOO gets more nuanced. While it’s marketed for use up to six months, most babies begin rolling as early as three or four months—and once rolling begins, any kind of swaddling becomes unsafe. Even before that point, it’s important to ask whether extended use might delay a baby’s chance to move and grow in their own way. A good rule of thumb? If your baby is awake, they should be out of the swaddle and on the floor as often as possible.

Another piece to consider is hip health. Traditional tight swaddling, especially when the legs are straight and pressed together, can increase the risk of hip dysplasia. The SNOO swaddle is designed with a looser fit at the hips, which helps—but it’s still crucial that babies' legs are free to flex and move into that natural “froggy” position. This positioning supports healthy joint development and reduces long-term risk.

And then there’s the issue of overheating. Swaddling a baby too tightly or layering on too many clothes can lead to overheating, which is a known risk factor for SIDS. The SNOO’s sleep sack is designed to help with this, but like with any sleep environment, caregivers need to be mindful—light layers, breathable fabrics, and a cool room are all key.

From a neurological perspective, we also think about reflex integration. Babies are born with reflexes like the Moro (or startle) reflex, which fade as their nervous systems mature. While swaddling helps reduce the suddenness of these reflexes and may prevent them from waking your baby, too much suppression—without enough time to move freely—can interfere with the natural fading of these reflexes. This doesn’t mean swaddling is harmful on its own, but it does mean that we need to balance the sleep support it offers with opportunities for awake movement and exploration.

The good news is you don’t have to choose between sleep and development. Swaddling can be part of a thoughtful, short-term strategy in those first few months. The SNOO can be a useful tool, especially during that tough newborn period. But like all tools, they work best when used intentionally and with awareness of when it’s time to move on.

As your baby approaches the three- to four-month mark, or starts showing signs of rolling, it’s time to begin transitioning away from swaddling and into more movement-friendly sleep environments. It doesn’t have to be abrupt—many babies do well with one arm out, then both, before fully moving into a sleep sack or pajamas. And during the day, giving your baby plenty of supervised tummy time, floor play, and free movement will support their physical and neurological development in all the right ways.

So if you’re using the SNOO—or swaddling in general—know this: it’s okay. You’re not doing anything wrong. These tools can be incredibly supportive, especially during those sleep-deprived early weeks. But when you’re ready, you can begin to make small shifts that prioritize movement, connection, and developmental growth. If you’re ever unsure of how your baby is progressing or want support in navigating transitions, a pediatric physical therapist can help you tune in to what your baby needs next.

You’re not alone in figuring this out. You’re learning your baby. And that learning is just as important as the sleep we all crave. Trust your instincts, ask for support, and know that you're doing an incredible job.

If you’re interested in learning about whether other often-hyped baby products are worth the buzz, check out my blog on marketing traps for new parents.

Dr. Rebecca Turkel is a Licensed Physical Therapist, Craniosacral Fascial Therapist, Certified Early Intervention Specialist, Certified Educator of Infant Massage, Certified in Neonatal Behavior Observation, and Integrative Breastfeeding Educator. 

Dr. Turkel has over 19 years’ experience working with families in an Early Intervention setting as a Developmental Specialist and Physical Therapist as well as 15 years’ experience working at Boston Children's Hospital as a Physical Therapist.