Fewer wet diapers than usual
Dark yellow or strong-smelling urine
Dry mouth or dry lips
No tears when crying
Sunken soft spot on the head
Sunken eyes
Lethargy or unusual sleepiness
Irritability or fussiness
Poor feeding or refusing feeds
Cool, mottled, or pale skin
Rapid breathing
Fast heartbeat
Weight loss
Less than 6 wet diapers in 24 hours after the first few days of life
Seek urgent medical care if the infant is very sleepy, hard to wake, has no urine for 8 hours or more, or shows signs of severe dehydration