Cesarean delivery increases offspring’s risk for Crohn’s disease

People who were delivered by cesarean section were more likely to receive a Crohn’s disease diagnosis later in life compared with their vaginally delivered counterparts, according to a population-based cohort study conducted in Sweden.

“The number of individuals born by cesarean section is increasing globally, with reported levels up to 20% of all deliveries,” Christine Hellsing, of the departments of surgery and clinical sciences at the Karolinska Institutet Danderyd Hospital in Stockholm, Sweden, and colleagues wrote. “This has encouraged the interest of a possible impact on health later in life in the offspring being born by [cesarean section]. One suggested significant factor in this context has been early exposure of offspring to bacteria. Although there is no consensus, if intrauterine life is sterile, then being born by [cesarean section] or vaginal delivery may have an impact on the gut bacterial colonization of the newborn.”

Using Sweden’s Medical Birth Register data from 1990 to 2000, Hellsing and colleagues identified 1,102,468 full-term babies, 11.6% of whom were delivered by cesarean section. They followed these individuals through the Swedish National Patient Register until 2017 to assess differences in the development of inflammatory bowel disease (Crohn’s disease or ulcerative colitis), appendicitis, cholecystitis and diverticulosis between people delivered vaginally vs. by cesarean section.

Unadjusted analyses revealed that cesarean section increased the odds of Crohn’s disease (HR = 1.13; 95% CI, 1.02-1.25), diverticulosis (HR = 1.57; 95% CI, 1.13-2.18) and cholecystitis (HR = 1.16; 95% CI, 1.05-1.28). After adjusting for confounders, only the odds for Crohn’s disease remained significant (adjusted HR = 1.14; 95% CI, 1.02-1.27).

The researchers also compared the risk for gastrointestinal diseases in people delivered by elective or emergency cesarean section. For those delivered through elective cesarean section, the risk for Crohn’s disease was higher compared with those delivered vaginally in both the unadjusted (HR = 1.16; 95% CI, 1.01-1.34) and adjusted (aHR = 1.18; 95% CI, 1.01-1.37) analyses.

On the other hand, people delivered by emergency cesarean section had a significantly greater risk for diverticulosis (HR = 1.63; 95% CI, 1.06-2.5) and cholecystitis (HR = 1.22; 95% CI, 1.07-1.39) compared with those delivered vaginally in adjusted analyses. However, that finding was no longer significant after the researchers adjusted for confounders.

Although Hellsing and colleagues emphasized a need for more research to determine the reason for this difference, they suggested “that individuals born by emergency [cesarean section] may have been exposed to vaginal flora during the beginning of the delivery compared with those born by elective [cesarean section], who have no exposure to vaginal flora.”