Newborn Behaviors Explained: The Strange, SweetThings Your Baby Does

Newborn behaviors can catch even the calmest parent off guard in those first few weeks. One minute your baby is peacefully asleep, the next they’ve thrown their arms out like they’re falling, or let out a sound that makes you check if they’re okay. If you’ve caught yourself Googling something your baby just did at 2 a.m., you are far from alone.

Most of these behaviors aren’t just normal — they’re actual signs that your baby’s nervous system, digestion, and senses are developing exactly as they should. This guide walks through 14 of the most common newborn behaviors, why they happen, and how to tell the difference between “this is completely typical” and “this is worth mentioning to your pediatrician or local health unit.”

(For more on what to expect once baby’s actually here, our Postpartum Essentials guide covers the recovery side of these early weeks too.)

1. The Startle Reflex (Moro Reflex)

This is the one that catches most parents off guard first. Your baby is resting, and suddenly their arms fly outward, their back arches slightly, and then they pull their arms back in, sometimes with a cry. This is called the Moro reflex, and it’s one of several primitive reflexes babies are born with, wired in before birth as a protective mechanism.

It’s triggered by a sudden change in position, a loud noise, being laid down, or even just a change in light. It usually fades somewhere between three and six months as the nervous system matures and voluntary movement takes over from reflexive movement. Swaddling can help some babies feel more settled through it, simply because it limits that sudden flailing sensation and mimics the snug feeling of the womb.

If your baby seems to startle constantly even in a calm, quiet room, it’s worth mentioning at a checkup — though for most babies, this is simply one of the more dramatic-looking newborn behaviors in the early weeks.

Jerky, Uncoordinated Movements

Newborns move in a way that can look almost robotic, arms and legs jerking rather than gliding smoothly. This is because the pathways between their brain and muscles, called myelination, are still being built. Think of it like wiring that hasn’t been fully insulated yet — the signals get through, but not always smoothly.

Over the coming weeks and months, movements gradually become smoother and more intentional as this wiring matures. There’s nothing to fix here — it’s simply one of the more visually striking newborn behaviors to watch unfold week by week — and it’s genuinely fascinating to look back at video from week one versus week eight and see the difference.

Snorting, Grunting, and Noisy Breathing

Newborns are nose breathers with very small nasal passages, so even a tiny bit of milk, mucus, or dried skin can cause a lot of noise. Grunting, snorting, and rattly breathing sounds are extremely common in the first few months, especially during sleep, when babies are lying flat and any congestion pools more noticeably.

As long as your baby’s breathing isn’t labored (meaning no flaring nostrils, no visible pulling in around the ribs, and no bluish tone to lips or face), their color looks normal, and they’re feeding well, this is simply a newborn being a newborn. A cool mist humidifier in the room, saline drops, or gentle nasal suction can sometimes ease the congestion-related sounds if they seem to be bothering your baby — though most of the time it bothers the parents listening far more than it bothers the baby.

Hiccups

It might seem odd how often newborns hiccup, sometimes several times a day, but their diaphragm is still learning to coordinate with feeding and breathing. Hiccups often happen after a feed, when a full stomach can trigger a bit of diaphragm spasm. They’re rarely bothersome to the baby, even if they look uncomfortable to us watching from the outside.

They typically resolve on their own within a few minutes, and there’s usually no need to intervene, though offering a bit more feeding or upright cuddle time can sometimes help. Like most newborn behaviors on this list, the best move is usually just patience.

Clenched Fists and Tucked-In Posture

For the first several weeks, babies often keep their fists clenched and their limbs curled in close to their body. This is simply a continuation of the fetal position they held in the womb for months, and it takes time for muscles to relax into a more open, stretched-out posture.

Over time, as their muscle tone develops and they get used to having actual space to move in, you’ll see their body slowly unfurl into more relaxed, open positions, often first noticeable during sleep.

Cross-Eyed Looks and Wandering Gaze

Newborn eye muscles are still developing coordination, so it’s completely normal for a baby’s eyes to occasionally cross, wander, or seem to move independently of each other in the first few months. This usually resolves on its own by around four to six months as eye muscle control strengthens — another example of newborn behavior that looks more concerning than it actually is.

Consistent crossing beyond that age range, or eyes that seem to cross constantly rather than occasionally, is worth mentioning at a checkup.

Sneezing More Than You’d Expect

Newborns sneeze frequently, and it’s rarely a sign of illness. Their nasal passages are simply clearing out amniotic fluid, dust, and general irritants, and sneezing is an efficient built-in way to do that. Unless it’s accompanied by fever, poor feeding, or other signs of being unwell, frequent sneezing is just part of a newborn’s normal nasal housekeeping.

Reflexive Smiling (Not “Real” Smiles Yet)

Somewhere in the first weeks, you’ll likely catch your baby smiling — often during sleep, and often when nothing funny is happening at all. These early smiles are reflexive rather than social; your baby’s nervous system is essentially testing out the muscle movement, not responding to a joke or your face just yet.

True social smiling, the kind that responds to you specifically, usually shows up around six to eight weeks. Until then, enjoy the reflexive ones anyway — they’re a genuinely lovely example of harmless, purely physical newborn behavior.

Rooting and Tongue Thrusting

If you stroke your baby’s cheek and their head turns toward your hand, mouth opening, that’s the rooting reflex — one of the most important feeding-related reflexes newborns have. Alongside it, you may notice your baby thrusting their tongue forward, especially when something touches their lips.

Both of these exist to help your baby find and latch onto a nipple or bottle, and they’re present from birth specifically because feeding can’t wait for a baby to “learn” it first. Rooting typically fades by around four months as feeding becomes a more intentional, learned behavior rather than a pure reflex.

Trembling Chin and Lips

A quivering chin, especially during crying, is extremely common in the first couple of months. It happens because a newborn’s nervous system is still building the fine motor control needed for smooth, steady muscle movement — the same immaturity behind the jerky limb movements covered earlier.

This kind of trembling should ease up by one to two months and typically only happens during crying or excitement, not at rest. Trembling that happens even when your baby is calm and not crying is worth a mention to your pediatrician.

Irregular “Periodic” Breathing During Sleep

Newborn breathing doesn’t look like adult breathing, and that can be unsettling to watch, especially at 3 a.m. It’s common for a newborn’s breathing to speed up, slow down, or even pause briefly (generally under 10 seconds) before catching back up with a few faster breaths. This is called periodic breathing, and it’s a normal part of an immature respiratory system still finding its rhythm.

It typically settles into a steadier pattern by around one month. A pause longer than 10 seconds, or breathing paired with a bluish tone to the lips or face, is not part of normal periodic breathing and warrants an immediate call to your pediatrician.

Twitching and Jerking During Sleep

Newborns spend a large portion of their sleep in “active sleep,” a lighter stage similar to REM sleep in adults, and it often comes with visible twitching, jerking limbs, or even brief startles while fully asleep. It can look alarming if you’re watching closely, but it’s simply one of the more common newborn sleep behaviors, tied to a normal, active stage of sleep.

This settles down as your baby’s sleep cycles mature over the following months, gradually shifting toward longer stretches of deeper, stiller sleep.

Peeling or Blotchy Skin

In the first one to three weeks, a lot of newborns go through a phase of peeling skin, especially on the hands, feet, and around the ankles. This is simply the outer layer of skin that developed in the womb’s fluid environment shedding as it adjusts to air. It’s not dryness in the usual sense, and heavy lotion use generally isn’t necessary; a gentle, fragrance-free moisturizer is enough if it seems to be bothering your baby’s skin at all.

You may also notice blotchy, mottled-looking skin, especially when your baby is a bit cool, which is a normal newborn circulation response and typically fades as they warm up or with time in the first few months.

The Palmar Grasp Reflex

Place a finger in your newborn’s palm, and their fingers will close around it, often surprisingly tightly. This is the palmar grasp reflex, and it’s strong enough in some babies that they can nearly support their own weight briefly, though that’s never something to intentionally test.

This reflex usually lasts until around five to six months, gradually replaced by voluntary, intentional grasping as your baby’s motor skills develop. It’s one of the more delightful newborn behaviors on this list, mostly because it’s the first “reach back” moment many parents get.

When to Actually Call Your Pediatrician

Most newborn behaviors covered here are genuinely normal, but a few signs are always worth a call regardless of what article or chart says is “typical”: labored breathing, a bluish tone around the lips or face, fever, unusual lethargy, a breathing pause longer than 10 seconds, or a noticeable change in feeding. Trust your instincts here over any list, including this one.

For a deeper, medically-reviewed look at newborn reflexes specifically, SickKids’ AboutKidsHealth is a trustworthy Canadian resource worth bookmarking.

Understanding these newborn behaviors early on can save you a lot of 2 a.m. worry — but if anything ever feels off, always check with your pediatrician. Every baby moves through these stages a little differently, and the range of “normal” here is genuinely wide.

If you’re also navigating your own recovery alongside all of this newborn-watching, our Postpartum Essentials guide covers what helps in these same early weeks. And if you’re still building out your registry or nursery, our Baby Registry Canada checklist and Sleeping Essentials guide are worth a look too, since a few of these behaviors (like periodic breathing and active sleep twitching) tie directly into how — and where — your baby sleeps.

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Frequently Asked Questions About Newborn Behaviors