By UTMB’s David Niesel and Norbert Herzog: In 1965, 4.5 percent of America’s babies were delivered via C-section. Today that figure has risen to almost one in three, and is on the rise worldwide as well. There are plenty of reasons for this shift from vaginal childbirth. Both come with side effects and consequences, some lasting longer than others. For example, C-sections have been linked to increased rates of diabetes and obesity, although we’re not sure why. In a recent study, birth by C-section lead to epigenetic changes in the child’s DNA. New research suggests certain epigenetic changes in a baby’s DNA called methylation are different depending on the type of birth. Distinct methylation changes were seen in more than 300 different regions of the genome between the babies delivered C-section and vaginal childbirth. Interestingly, many of these regions are associated with genes that control the immune system. We don’t know how these epigenetic changes affect the immune system and ability to fight disease, and don’t have sufficient information to link these differences to later health issues. But this remains an intriguing possibility and awaits more research.