Giving women a type of epidural jab to relieve pain in the early stages of labour does not increase the odds of a Caesarean section, research suggests.
Birth can be a painful experience all round
Previous research had suggested the numbing effect of the painkiller affected a woman's ability to push and that led to more Caesarean deliveries.
But research on 750 pregnant women in Chicago found no increased risk from a low-dose jab called a spinal-epidural.
Lead researcher Dr Cynthia Wong said it showed more women should get the jabs.
A Caesarean section is a major operation which carries a heightened risk of complications, both for mother and child.
A standard epidural injection works by depositing local anaesthetic drugs into the space just outside of the spinal cord.
It anaesthetises the abdominal, genital and pelvic areas.
Slows down labour
But there is concern that it might also slow down contractions, and thus the progress of labour.
The research team, from Chicago's Northwestern University, reported in the New England Journal of Medicine that they had used a variant called a combined spinal-epidural, which is thought to have a lesser impact on mobility.
This involves injecting the first dose of anaesthetic directly into the fluid around the spinal column.
The researchers focused on 750 pregnant women who were giving birth for the first time.
They found 18% of women who were given an epidural during the early stages of pregnancy went on to have a Caesarean delivery - compared with 21% of those given general pain relief until they were at least 4cm dilated.
This second group did eventually receive an epidural - but not until their labour was more progressed.
The average time between receiving an epidural and becoming fully dilated was 295 minutes, compared with 385 minutes for those given general pain relief in the early stages of labour.
The women given an epidural also reported lower levels of pain.
No need for guilt
Lead researcher Dr Cynthia Wong said: "Women often feel guilty or weak when they request an epidural early in labour.
"I hope this study will help women see that there is no shame in asking for an epidural.
"The message for women and their obstetricians and gynaecologists is that there is no reason why women who want an epidural should not get it when they first request it."
Dr David Bogod, editor of the journal Anaesthesia, said there was a feeling, particularly among midwives, but also obstetricians in the UK, that early epidurals should be avoided.
"This is a well conducted, very powerful study that completely puts the mockers on that - this is a very clear result indeed," he said.
Dr Bogod also said use of an epidural meant that other forms of powerful pain relief, which could extend labour, and sedate the baby, would not be needed.
However, he said there was still a vocal lobby opposed to epidurals on the grounds that they somehow promoted unnatural modes of delivery.