Children born by C-section not at increased risk of developing obesity, finds study which debunks notions about such an association
Women who have C-sections are no more likely to have children who develop obesity than women who give birth vaginally.
Based on their findings, the research team from Karolinska Institutet in Sweden says that how women give birth is not an important factor in determining the risk of obesity in children. The findings contradict several smaller studies that did find an association between C-section deliveries and child obesity. According to the research team, such studies did not consider the numerous maternal and prenatal factors, which were part of the current study.
According to the analysis, 5.5% and 5.6% of male children delivered through elective and non-elective C-section, respectively, were obese as compared to 4.9% of the male children delivered vaginally.
However, after accounting for other factors known to impact children's weight - including pre-pregnancy BMI, maternal and gestational age and the presence of diabetes, hypertension, smoking and preeclampsia in the mother - the researchers concluded that the method of childbirth did not play a significant role in determining the risk of obesity in the child. The findings have been published in PLOS Medicine.
"It has been suggested that cesarean section may increase the risk of obesity in the offspring. However, we were not able to see such a difference in the development of obesity when we conduct the hereby largest study on differentiated forms of cesarean section and offspring obesity," Viktor H. Ahlqvist, a researcher at the Department of Global Public Health, Karolinska Institutet, told MEA WorldWide (MEAWW).
"Indeed, we observed descriptive differences. However, when accounting for prepregnancy maternal BMI, maternal diabetes at delivery, maternal hypertension at delivery, maternal smoking, parity, parental education, maternal age at delivery, gestational age, birth weight standardized according to gestational age, and preeclampsia, we observed no difference between vaginal deliveries and cesarean sections. We note that accounting for prepregnancy maternal BMI completely removed any difference between vaginal delivery and cesarean section. As such, we conclude that the mode of delivery is not associated with the development of obesity in the offspring," Ahlqvist told MEAWW.
Globally, the number of babies born through a cesarean section or C-section almost doubled between 2000 and 2015 - from 12% to 21% of all births - according to a series of three papers published in The Lancet last year.
The jump has sparked intense research into the long-term consequences of C-section on children's health, and several studies have linked cesarean deliveries with increased risks for asthma, various allergies, and obesity.
The association with obesity has, however, mainly been confirmed in smaller studies that were "unable to account for a wide array of possible confounders or differentiate between types of C-sections," says the team.
In the current study, researchers investigated if increased C-section births could explain part of the rise in obesity also seen in the last decades and whether this potential association held true once they accounted for maternal and prenatal factors known to impact the child's weight. They compared the body-mass index (BMI) of nearly 100,000 male 18-year-olds and divided them into categories depending on whether they were born through vaginal delivery, elective C-section, or non-elective C-section.
"We found no evidence to support a link between C-sections and the development of obesity. This tells us that how women give birth may not be an important factor in the origins of the global obesity epidemic," says Daniel Berglind, researcher at the Department of Global Public Health, Karolinska Institutet.
The researchers also identified nearly 10,000 full brothers and concluded that sibling analysis, accounting for genetic and environmental factors, did not alter the overall findings.
According to Ahlqvist, most of the association between C-section and obesity could be explained by maternal pre-pregnancy BMI.
The team explains the "strongest confounder in the association between mode of delivery and obesity" was how much the mother weighed before she became pregnant. This is consistent with previous reports on the heritability of obesity and the influence of maternal obesity on fetal health, says the team.
"This suggests that heritability and fetal exposure to obese-causing factors in the womb are more important when assessing the risk of obesity in the offspring than the mode of delivery," says Ahlqvist.
The findings, say Ahlqvist, highlight that healthcare professionals, mothers, children, and society should not be alarmed that those born of a cesarean section would be at an increased risk of developing obesity.
"A mother and clinician should not be discouraged of cesarean section on the basis of a postulated increased risk of obesity in offspring. Finally, cesarean sections may not serve a role in the obesity epidemic and, as such, should not be a target for intervention when attempting to reduce the burden of obesity," Ahlqvist told MEAWW.