Newborn Reflexes: Startle, Rooting, Grasp and When They Fade

Why reflexes matter

• Newborns arrive with built-in automatic movements. They help with feeding and protection, and checking them is part of every newborn exam.
• As the brain matures, most fade over the first months and are replaced by deliberate movement. The ages below are typical ranges; individual babies vary.

The main reflexes

• Startle (Moro): a sudden noise, movement or feeling of falling makes the baby fling arms and legs out, open hands, then pull arms back in, often with a cry. Strongest in the first month; usually gone by about 4-6 months. It's why many babies wake themselves and why swaddling or a hand on the chest can help (see the swaddling guide).
• Rooting: stroke the cheek or corner of the mouth and the baby turns toward it with an open mouth, searching for a feed. Useful for latching. Fades around 4 months as feeding becomes voluntary.
• Sucking: anything touching the roof of the mouth triggers rhythmic sucking. Present from late pregnancy; premature babies may have a weaker or less coordinated suck at first.
• Palmar grasp: press a finger into the palm and the baby grips tightly. Fades around 5-6 months, when deliberate reaching and grabbing take over.
• Plantar grasp: press the sole below the toes and the toes curl. Lasts until about 9-12 months.
• Tonic neck (fencing): when the head turns to one side, the arm on that side stretches out and the other arm bends up by the head. Fades around 5-7 months.
• Stepping: hold the baby upright with feet on a flat surface and they make walking movements. Usually gone by about 2 months. It returns as real walking much later.
• Babinski: stroke the sole from heel to toe and the big toe goes up while the toes fan out. Normal in babies, often until 1-2 years.

Other normal newborn movements

• Jittery or trembling chin, arms or legs, especially when crying or cold, which stop when you hold the limb gently.
• Sudden jerks while falling asleep (sleep starts).
• Sneezing, yawning, hiccups and gagging are reflexes too.

Fun, gentle ways to notice them

• Let the baby grip your finger during a feed or diaper change.
• Watch the fencing pose when the baby turns to look at you.
• No need to test reflexes repeatedly; it can be upsetting, especially the startle.

Reflexes and development

• Reflexes fading on time is one sign the nervous system is maturing. The pediatrician checks them at well visits.
• Premature babies often follow their adjusted age (see the preemie guide).

When to check in

• Mention at a checkup if a reflex seems missing, much weaker on one side, or still strong well past the usual range, or if one arm moves less than the other, which can follow a stretched nerve or a collarbone injury at birth.
• Rhythmic jerking that doesn't stop when you hold the limb, with staring, lip smacking or color change, may be a seizure; call 911.