If epidurals were controlled by women while they were in labour, the need for medical intervention can be reduced, according to scientists.
A conference in the US was told that women given spinal pain relief tended to use less anaesthetic and also tended not to require a forceps delivery.
Epidurals are given to around 40% of women in the UK and are administered at a constant rate, although only around one in five hospitals allow women to control the amount of drug dispensed.
Researchers at Long Beach Memorial Medical Center, California, looked at the cases of 270 women, two thirds of whom were administered a steady flow of drugs. The other third had a hand-held controller to control the flow themselves, although they could only press the button after set periods of time.
Those given patient-controlled epidural analgesia were found to use around 30% less anaesthetic, the researchers said.
Patient satisfaction was roughly the same but the women controlling their own drugs were in more pain during the final stage of labour.