Long Term Consequence of Mild Oxygen Loss During Delivery, 3/1998 

Severe and prolonged loss of oxygen (severe hypoxia) to the infant during delivery can cause or contribute to brain damage and to physical and cognitive difficulties. 

When there is a modest loss of oxygen (mild hypoxia) for an extended period, the consequences are less understood. If the infant with a mild degree of oxygen deprivation demonstrates no evidence of brain damage at birth and/or during the first year of life, does that mean the child will not show evidence of brain damage as it grows older (e.g.: when he/she enters school)? 

A pediatric research group in Canada has studied this question in full term infants (they used full term infants to avoid the complicating issue of prematurity).¹ They compared the motor skills, cognitive developed memory and child behavior of two groups of children at age 4, and then again at 6-8 years of age. One group had experienced mild oxygen deprivation during delivery but no immediate evidence of brain damage; the other group had no bio-chemical or clinical evidence of hypoxia. The two groups were otherwise similar ("matched"). 

When examined at 6-8 years of age, there were no differences in performance between the two groups. Mild hypoxia did not result in performance deficits or signs of developmental brain damage in full term infants when compared to the group which did not experience mild hypoxia. 

Comment: It has been suggested that while mild oxygen deprivation during delivery does not usually result in immediate loss of brain function, there might be a modest loss of function as the child matures. This study indicates that this is probably not true. Brain injured children can certainly demonstrate difficulties in motor performance or in cognitive abilities for the first time at school age even though there was no overt evidence of such during infancy or early childhood; however, these difficulties are probably not due primarily to mild hypoxia during the birthing process. The causes for delayed evidence of difficulties probably occurred during infancy or childhood, sometimes because of a pre-existing sensitivity to brain injury due to intrauterine factors. 

¹ Handley-Derry, M., et al. Intrapartum Fetal Asphyxia and the Occurrence of Minor Deficits in 4 and 8 Year Old Children. Developmental Medicine and Child Neurology (1997); 39: 508-511. 

© UCP Research & Educational Foundation, March 1998

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