A team of researchers at the Yale School of Medicine, in New Haven, Connecticut, has found that vaginal birth triggers the expression of a protein, UCP2 (mitochondrial uncoupling protein 2), in the brains of newborns that improves brain development and function in adulthood. It influences neurons and circuits in the hippocampus, the area responsible for memory.

The protein is also involved in the cellular metabolism of fat, a key component of breast milk, suggesting that induction of UCP2 by natural birth may aid the transition to breastfeeding. The researchers also found that this protein expression is impaired in the brains of babies delivered by Caesarean section.

These results suggest, “The increasing prevalence of C-sections, driven by convenience rather than medical necessity, may have a previously unsuspected lasting effect on brain development and function in humans,” observes Tamas Horvath, chair of Yale’s Department of Comparative Medicine.