THE EFFECT OF MATERNAL OXYGEN ADMINISTRATION ON HUMAN FETAL CEREBRAL OXYGENATION MEASURED DURING LABOR BY NEAR-INFRARED SPECTROSCOPY

Objective To test the hypothesis that intrapartum maternal oxygen admi nistration increases fetal cerebral oxygenation during normal labour. Design A prospective study comparing changes in fetal cerebral concent rations of oxyhaemoglobin, deoxyhaemoglobin and cerebral blood volume measured by near infrared spectroscopy, before, during and after mater nal oxygen administration using a 60 % Ventimask. Setting Teaching hos pital obstetric unit. Subjects Ten term fetuses during uncomplicated l abour. Results Maternal oxygen administration for 15 min resulted in a significant increase in the mean concentration of fetal cerebral oxyh aemoglobin (0.78 mu mol (SD 0.42) 100 g(-1) brain tissue, P < 0.001) a nd a significant decrease in the mean concentration of deoxyhaemoglobi n (0.80 mu mol (SD 0.51) 100 g(-1), P < 0.001). These changes were ass ociated with a significant increase in the calculated mean cerebral ox ygen saturation from 43.9 % (SD 6.3) to 57.3 % (SD 5.6) (P < 0.001). T he maximum rise in cerebral oxyhaemoglobin concentration occurred at a mean of 10.7 min (SD 3.9) following commencement of oxygen administra tion. On returning to air breathing these changes reversed. There were no changes in cerebral blood volume. Conclusion Maternal oxygen admin istration during normal labour leads to a significant rise in fetal ce rebral oxygenation.