What is the chance if my son had hie that he will have problems with mental retardation in the future?

Depends: This depends on the severity of their hie, how they are treated, and how quickly they recover. Elevated body temperature should be avoided and they should probably undergo therapeutic hypothermia. Most sarnat (a grading scale) "mild" and "moderate" hie patients have normal outcomes while virtually all "severe" hie patients have future problems. Eeg/mri may give additional predictive information.

Need close follow up: Certain probabilities can be stated based upon the degree of hie that your son suffered. More severe hie can be associated with significant neurologic impairment. Mild hie may be associated with minimal or no long term problems. Follow up with early intervention services for physical therapy, occupational therapy, and speech therapy, neurology and a developmental pediatrician are important.

Risk factors: The sarnat neurological score, physical findings and eeg results in a newborn helps predict risk of developmental delays/ intellectual disability/cerebral palsy. Infants with stage 1 mild symptoms for <24 hours or moderate symptoms stage 2, for < 5 days have low risk. Higher risk is stage 2 > 7 days. Stage 3 severe symptoms + seizures on eeg, 70% risk.A type of MRI (dwi) can show injury early.