Women having babies would be asked to pay for epidurals under a proposal from the Royal College of Midwives.
Epidural is one form of pain relief used during labour
Its education and research committee says too many have the pain-relieving injection, given to a fifth of pregnant women.
Critics said the proposal, to be debated at the RCM conference, would discriminate against poor women.
And the Department of Health ruled out charging for the treatment - which can cost up to £500 in private clinics.
An epidural is a local anaesthetic injected into the spine which numbs the lower half of the body so a woman does not feel pain of contractions during labour.
The education and research committee's motion states that epidurals should be "free to women who have a definite need of it" but says a fee should be "levied for all other women who desire an epidural".
Sue Macdonald, chairman of the RCM's education and research committee which came up with the proposal, told the Daily Telegraph: "There is quite a lot of research around which suggests that although it is an effective form of pain relief, an epidural means women will have to spend longer pushing the baby out of the birth canal and are more likely to need other interventions.
A review of 21 studies carried out last year comparing women who had had epidurals with those who had not, found those who had the injection were 40% more likely to need interventions such as forceps or a ventouse vacuum pump.
Ms Macdonald added: "Epidurals have become a kind of norm for a lot of women.
"Sometimes women think 'I just want to get rid of the pain, how fantastic'."
The leadership of the RCM says this is an issue which members are concerned about - and the motion would therefore be debated at its conference in May.
If it is passed, the RCM would lobby health departments in a bid to persuade them to implement a charge.
Louise Silverton, RCM Deputy General Secretary, said: "Epidurals provide effective pain relief but, where there is no clinical indication that they are necessary, they can significantly raise the likelihood of other interventions such as Caesarean section occurring.
"The UK already has an extremely high Caesarean rate and, as the acknowledged experts in normal pregnancy, labour and birth we midwives need to debate ways in which we might help to bring this rate down."
Ms Silverton added: "This is a very serious issue and one that is likely to raise significant debate but also something that needs to be debated if we are to improve the normal birth rate."
But Mary Newburn, of the National Childbirth Trust, said: "The NCT does not support the proposal to charge women for an epidural.
"This would be adding insult to injury when women are often denied access to other options that would help them cope during labour.
"It is also an impossible judgement call to decide some women 'need' an epidural for pain relief and others don't.
"We need to build up women's confidence so that they can cope with the pain of a normal labour rather than take away one of the choices that they have come to expect."
A spokesman for the Department of Health ruled out the idea of charges altogether.
He said the government had pledged to introduce a choice of pain relief for all women by 2009.
But he added: "We would not charge for pain relief."