The fundi of 87 full-term newborns were repeatedly photographed from 2 to 144 h of life. At 2 h of life the width of the temporal arteries in the peripapillary area was about 100 micrometers and that of the nasal arteries about 70 micrometers, and all gradually decreased by about 30% during uneventful adaptation in room air. This decrease did not correlate with concomitant tcpO2 and blood pressure measurements. In most babies the arteries were slightly tortuous at 2 h of life and gradually straightened during adaptation. In some babies, however, there was marked tortuosity at 2 h of life, and this finding was significantly correlated with fetal risk factors. We conclude that marked tortuosity is a sign of passed acute fetal distress and that funduscopy in risk babies should be promoted.