The care women receive when giving birth in England varies depending upon where they live, and this variation is concerning, a new report has concluded.
The Royal College of Obstetricians and Gynaecologists' reviewed more than 550,000 births and said there is a "substantial variation" in practice between NHS maternity units.
The review, conducted jointly with the London School of Hygiene and Tropical Medicine, highlighted different rates of emergency caesarean sections, instrumental deliveries and episiotomy between 2013 and 2014.
"We are concerned about the amount of variation identified in this report," said RCOG president Dr David Richmond.
"Although the exact causes are difficult to establish, it is paramount that maternity units have information about their services, as well as the ability to compare themselves to the national average and to their peers."
In some maternity units 8% of mothers needed emergency c-sections but in others the figure was 15%, the review found.
The number of first-time mothers who gave birth naturally but needed help with instruments also varied from just under one in five in some units, to almost three in 10 in others.
The number of women who needed an episiotomy [an incision in a woman's perineum (the area between the vagina and anus) during the process of giving birth] ranged from 29% to 44%.
"The RCOG is dedicated to creating a culture of openness and transparency within maternity and gynaecological care," added Dr Richmond.
"With this information, maternity services, alongside commissioners, will be able to move towards identifying priority areas for reducing variation and further improving the safety and quality of care provided to women and their babies."
Commenting on the report, Louise Silverton, director for midwifery at The Royal College of Midwives said she is also concerned about variation between maternity services and the care they provide.
"It is unfortunate that this continues and is mirrored in outcomes of still birth rate and perinatal deaths," she said.
"While it is normal to see some variation in clinical practice, it must be remembered that it is women and babies who experience these variations in practice and there needs to be more information provided for women to enable them to choose where they want to have their care."
Health Minister Ben Gummer said, according to PA: "Mothers and their babies deserve the very highest standards of care regardless of where they live.
"The NHS is already a safe place to give birth and by being open and honest about variations in care RCOG's report will help the NHS to improve the care it provides and build a safer NHS seven days a week."