Oxygen at Caesarean section : too much of a good thing? : guest editorial

Paracelcus (1493-1541), a scientist of the Middle Ages, exclaimed: "All things are poison and nothing is without poison; only the dose permits something not to be poisonous". Might this be true of oxygen during Caesarean section? Should oxygen, like most other drugs that we use in medicine, be administered within a tight therapeutic range, where too much of the drug may result in side-effects, but too little will allow insufficient benefit to be conferred by the drug on the patient? Should oxygen only be administered when indicated; thoughtfully and for a limited duration, with the dose being reviewed at regular intervals?