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This could be typical of a Breath holding spell in infants aged over 6 months of age. It is usually seen when infants are frustrated. Nothing to worry. But it should be differentiated from seizures and heart rhythm problems. It would be best to consult your Paediatrician and get an ECG done as well as get his blood haemoglobin
checked as anaemic infants are more prone to develop worsening spells. There are various treatment approaches which can be discussed with his Doctor.