Nearly one in three pregnant women in England is having labour induced – an increase from one in five 10 years ago, according to figures from NHS Digital.
Rising numbers of older and overweight women giving birth is behind the trend, experts say.
Induced labours are usually started with pills or gels, often because babies are large or overdue.
Women should be encouraged to keep to a healthy weight before and during pregnancy, doctors advise.
Last year, in 2017-18, NHS data shows labour started naturally for 52% of babies delivered in hospital, and this was down from 69% in 2007-08.
The most common method of delivery was spontaneous vaginal delivery – except among women over 40 years old, where caesareans accounted for more.
Pat O'Brien, consultant obstetrician and spokesman for the Royal College of Obstetricians & Gynaecologists, said women over 40 giving birth were not allowed to continue past their due date and this was pushing up inductions.
"The average age of women giving birth is rising all the time," he said.
"They are also more likely to have pre-existing problems, such as type 2 diabetes and high blood pressure, which create complications.
"And with the rise in obesity, more women are likely to have bigger babies which leads to more inductions."
However, he said induction was a safe procedure which could reduce some risks and did not necessarily lead to a caesarean, as was previously thought.
Why are labours induced?
- if a woman is overdue and does not go into labour naturally (or spontaneously) by 42 weeks, or 40 weeks for the over-40s, there is a higher risk of problems or stillbirth after this time
- if a woman's waters break early – more than 24 hours before labour starts – bringing an increased risk of infection to her and the baby
- if a woman or her baby have a health condition and do not seem to be thriving
The NHS figures show planned caesareans are also increasing – from 11% in 2007-08 to 16.2% in 2017-18.
Dr O'Brien said: "The majority of elective caesarean births are performed for medical reasons, such as a baby being in a breech position, and some may be offered in response to maternal choice, which should also be supported."
He added: "Women must be informed about the benefits and risks of the different ways to give birth, which will differ for each woman based on her individual case, pregnancy and medical history, so she can make an informed decision."
And he said it was important that women and men were encouraged to maintain a healthy weight before conception and women keep to a healthy weight during pregnancy to reduce the risk of complications.
Other maternity data collected for most – but not all – deliveries in England last year, shows that most newborns weighed between 3kg and 3.49kg at birth and 74% of babies had breast milk as their first feed.
One in four women over 40 giving birth was obese (with a BMI over 30) while 31% of women under 20 said they were smokers.
The Royal College of Midwives said this was "far too high" and should be tackled "as matter of urgency".