Brain damage after intermittent partial cord occlusion in the chronically instrumented fetal lamb.

The relationship between intermittent partial occlusion of the umbilical circulation and fetal acid base status, brain function, and neuropathologic outcome was assessed in nine control and nine experimental singleton fetal lambs to determine if transient episodes of partial cord occlusion play a role in antenatal brain damage in this species. Intermittent partial occlusion of the umbilical circulation for 1 minute of every 3 minutes for 2 hours was associated with a 89% incidence of histologically confirmed damage confined to the cerebral white matter. This occurred without systemic evidence of progressive acidosis, but both fetal heart rate patterns and electrocortical activity were altered. We conclude that in the late gestation fetal lamb, umbilical cord compromise plays a causal role in a specific type of antenatal central nervous system injury.