Wide variations in the rate of caesarean sections carried out in Europe have raised concerns about whether women are benefiting from best practice, researchers have said.
A new study published by the journal BJOG has found around a quarter of births in the UK are by C-section, compared to a low of 14.8% in Iceland and a high of about 52% in Cyprus.
Authors of the study, led by academics at City University London, said it highlights a clear "lack of consensus about best practice" between countries of the EU, Norway, Switzerland and Iceland.
It urged further investigation, suggesting professionals' attitudes to care at delivery, adherence to guidelines and differences in healthcare systems and how they are financed could be to blame for the stark variations.
Alison Macfarlane, professor of perinatal health at City University London and lead author of the study, said: "We would hope that this data would be consistent but it clearly isn't.
"There is a concern that the caesarean rate is going up and there are some women who undergo the surgery unnecessarily, which this reports suggests there are because of the wide variation.
"The UK figures are neither high nor low, but there is a concern that the caesarean rates are still going up, with huge variations even between hospitals.
"When a caesarean is really necessary it can mean the difference between life and death but but when it isn't it can have big effects on the mother and the baby.
"We need to look at what are the pressures that lead to more caesareans and why is there such wide variation in clinical practice."
She highlighted the need for a comparative review of national policies and guidelines to prioritise the health of mothers and children
The study, the first of its kind, found the average of rate of C-sections in Europe is around 25.2% of all births.
However, the figure for mothers giving birth to more than one baby is 63.1%, and is 98.6% in Malta, 31.1% in Iceland and 62.6% in England. Data for all the UK was not available.
C-sections are more likely to be performed when babies are born to first-time mothers, women who have previously undergone a caesarean or who are carrying twins or when babies are in a breech position.
The study was based on data collected in 2010 from "routine sources" to explore differences childbearing populations.