Babies delivered by Caesarean section may be at increased risk of becoming obese later in life compared with those born by natural delivery, suggests the new study from Imperial College of London, which was published in the journal PLOS ONE, according to Fox News.

And the odds of being overweight as an adult were 26 percent higher for those born by C-section, according to the authors, who reviewed information from 15 previous studies that collected data on individuals' method of delivery when they were born, as well as their body mass index (BMI) in adulthood from more than 38,000 people from 10 countries.

Currently, about a third of babies born in the United States, and a fourth of babies born in England, are delivered by C-section, which is twice more than in 1990. In a number of countries this figure is much higher, for example, in China and Brazil, where such operation is done to 60% and 50% of parturient women correspondingly. BMI of babies born with the help of surgery was by 0,5 more, compared with those born by vaginal delivery.

The scientists plan to determine what plays a key role. As an argument in favour of their theory they say, that passage through the birth canal affects the composition of intestinal microflora, and compression during labor can "turn on" certain genes, which has a long-term effect on the metabolism.