Children delivered by cesarean section are twice as likely as children born vaginally to become obese, according to study results.
“Almost one in three children in the US are delivered by cesarean section,” study researcher Susanna Huh, MD, told Healio.com “If cesarean delivery is a risk factor for obesity, then this would be another reason to avoid cesarean sections that aren’t medically necessary.”
Huh, director of the Growth and Nutrition Program at Children’s Hospital in Boston, along with Harvard Medical School colleagues conducted a prospective pre-birth cohort study, titled “Project Viva,” that enrolled women in eastern Massachusetts during early pregnancy between 1999 and 2002. Modes of delivery were identified through electronic hospital records. The researchers included 1,255 children in the study, measuring body composition at 3 years of age.
The researchers used multivariable linear regression models to assess the relationship between cesarean deliveries and BMI scores, and multinomial logistic regression to assess the associations between cesarean section births, overweight and obesity. Participants with a BMI less than the 85th percentile were used as the comparison group. The researchers adjusted for maternal age, race, ethnicity, education and BMI, as well as child age, sex and birth weight.
Results showed that 284 children (22.6%) were delivered by cesarean section. At 3 years of age, 15.7% of participants delivered by cesarean section were obese vs. 7.5% of participants born vaginally. Cesarean sections were associated with higher odds of obesity at 3 years of age (OR=2.10; 95% CI, 1.36-3.23), higher mean BMI z scores (0.2 units; 95% CI, 0.07-0.33) and higher sum of triceps and subscapular skinfold thickness (0.94 mm; 95% CI, 0.36-1.51).
The researchers said they were unable to examine the potential reasons underlying the relationship between cesarean section births and childhood obesity. However, they wrote that one possible explanation may be the differences in the composition of intestinal bacteria.
“Differences in child intestinal flora according to mode of delivery have been noted in the first year of life, a period of dramatic changes in number and diversity of gut microbes as well as rapid growth,” they wrote. “Most, but not all studies, suggest that infants delivered by cesarean section have higher stool quantities of members of the Firmicutes group, or lower quantities of the Bacteroidetes group.” Huh said she and her research team speculated that these differences in bacteria quantities may influence a child’s body composition.
Another possibility, the researchers wrote, could involve the routine use of perioperative antibiotic prophylaxis during cesarean deliveries, which could change the composition of neonatal intestinal flora and, therefore, lead to the development of obesity. The researchers added that further research is needed to confirm these findings and explore the link between cesarean section births and childhood obesity.
Disclosure: The researchers report no relevant financial disclosures.