Startle or Seizure? Telling Your Baby’s Normal Movements from Seizures

If your baby suddenly startles or trembles in their sleep, it is natural to worry. The reassuring news is that most sudden baby movements are normal and fade as your baby grows. A few simple signs help you tell when a movement is normal and when it needs a medical check.

Normal movements that are not a worry

• The startle (Moro) reflex: your baby suddenly flings their arms out at a loud noise or when moved, then brings them back in. It settles when you hold them or gently hold their hands.
• Chin or hand jitters: light trembling while crying or waking, which stops when you touch your baby or hold their hand still.
• Sleep twitches: brief jerks of the arms or legs during sleep only, which stop as soon as your baby wakes.

Signs that may point to a seizure

• The movement does not stop when you hold your baby’s hand or cuddle them.
• Sudden forward bends or stiffening that come in clusters, especially on waking.
• A fixed stare or unusual eye movements, or not responding to your voice during the movement.
• Lips or face changing colour, or repeated chewing or sucking movements for no reason.
• Marked sleepiness or confusion once the movement stops.
• Your baby smiling, connecting or doing less after these movements began.

What to do if you think it is a seizure

1. Stay calm and lay your baby on their side somewhere safe.
2. Put nothing in their mouth, and do not try to stop the movement by force.
3. Check the time and film a short video if you can; it is one of the most helpful things for the doctor.
4. If it lasts more than 5 minutes, or comes with trouble breathing or a blue colour, call an ambulance or go to the nearest emergency department.

How the clinic assesses it

We start by listening to you and watching your video, followed by a simple neurological check of your baby. If needed, we ask for an EEG, which uses small painless stickers on the head, and sometimes a brain MRI or other tests. The aim is to reassure you if the movement is normal, or to start treatment early if it is a seizure.