Women who eat healthily and stay active during pregnancy cut their chance of needing a caesarean section by about 10 per cent, British experts say.
A review of 36 studies in 16 countries found a careful diet and exercising helped reduce excessive weight gain in pregnancy and enabled more women to deliver naturally.
Although regarded as very safe, caesareans can carry a risk of complications.
These include the risk of infections to new mothers, excessive bleeding and potential damage to surrounding organs.
Risks to the baby include breathing problems, which are fairly common and mostly affect babies born before 39 weeks gestation.
This usually improves within a few days.
Of the studies in the new analysis, 23 included women of any weight at the start of the study, seven included obese women only and six were targeted at overweight and obese women.
The researchers, writing in the British Medical Journal, found women of any weight offered tailored diet and exercise advice during pregnancy were less likely to need a caesarean or gain excessive weight.
There was also some evidence that they were less likely to develop diabetes in pregnancy.
The advice on dieting included restricting sugary drinks, switching to low-fat dairy and eating more fruit and vegetables.
Exercise programs included aerobic classes and cycling in the gym, and some weight-based training.
The study was led by experts at Queen Mary University of London using data from more than 12,000 women.