Caesarian sections are on the rise in the United States, but a new study out yesterday indicates that the surgical birth method may have an unexpected consequence. It found that babies born by C-section are twice as likely to be obese by age three, reports the Washington Post. Researchers reviewing the records of 1,255 mothers and babies discovered that 7.5% of those born vaginally were obese at three, vs. 15.7% of those born by C-section.
The Post notes that while both the mothers and babies in the C-section group were heavier, the researchers controlled for factors like the mother's weight, baby's size, and how long the baby was breastfed. The researchers' theory: The surgical procedure could affect how babies acquire important digestive bacteria from their mothers, which could in turn alter the way their bodies digest food. Babies born by C-section rose to 32% in 2007, up from 20.7% in 1996. (Another possible obesity factor? Fungicide.)