The effect of maternal oxygen administration on human fetal cerebral oxygenation measured during labour by near infrared spectroscopy.

OBJECTIVE

To test the hypothesis that intrapartum maternal oxygen administration increases fetal cerebral oxygenation during normal labour.

DESIGN

A prospective study comparing changes in fetal cerebral concentrations of oxyhaemoglobin, deoxyhaemoglobin and cerebral blood volume measured by near infrared spectroscopy, before, during and after maternal oxygen administration using a 60% Ventimask.

SETTING

Teaching hospital obstetric unit.

SUBJECTS

Ten term fetuses during uncomplicated labour.

RESULTS

Maternal oxygen administration for 15 min resulted in a significant increase in the mean concentration of fetal cerebral oxyhaemoglobin (0.78 mumol (SD 0.42) 100 g-1 brain tissue, P < 0.001) and a significant decrease in the mean concentration of deoxyhaemoglobin (0.80 mumol (SD 0.51) 100 g-1, P < 0.001). These changes were associated with a significant increase in the calculated mean cerebral oxygen saturation from 43.9% (SD 6.3) to 57.3% (SD 5.6) (P < 0.001). The maximum rise in cerebral oxyhaemoglobin concentration occurred at a mean of 10.7 min (SD 3.9) following commencement of oxygen administration. On returning to air breathing these changes reversed. There were no changes in cerebral blood volume.

CONCLUSION

Maternal oxygen administration during normal labour leads to a significant rise in fetal cerebral oxygenation.