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Cesarean baby 15% more likely to become obese

Cesarean born babies are 15% more likely to become obese as children than individuals born by vaginal birth and 64% more likely to be obese than their siblings born by vaginal birth. The increased risk may persist through adulthood. All of this data is according to a large study from Harvard T.H. Chan School of Public Health.

Researchers also found those born vaginally by women who had undergone a previous cesarean delivery, were 31% less likely to become obese compared with those born via cesarean birth immediately following a cesarean birth.

The study was published September 6, 2016 in JAMA Pediatrics.

"Cesarean deliveries are without a doubt a necessary and lifesaving procedure in many cases. But cesareans also have some known risks to the mother and the newborn. Our findings show that risk of obesity in the offspring could be another factor to consider."

Jorge Chavarro PhD, Associate Professor, Nutrition and Epidemiology, Harvard Chan School of Public Health, Boston, Massachusettes, USA, and senior author of the study.

Nearly 1.3 million cesareans are performed each year in the U.S., accounting for one third of all deliveries. While a number of previous studies have suggested a link between cesarean delivery and a higher risk of obesity in offspring, the studies were either too small to detect a clear association or lacked detailed data.

The new analysis included 16 years' worth of data from more than 22,000 young adults in the Growing Up Today Study (GUTS).

Participants answered questions every one or two years from 1996-2012 for:
   (1) participants' body mass index (BMI) over time
   (2) whether or not mom was delivered via cesarean herself
   (3) obesity factors: pre-pregnancy BMI, smoking?, age, where living
   (4) whether mom had previous cesarean deliveries prior to recorded one

"I think that our findings — particularly those that show a dramatic difference in obesity risk between those born via cesarean and their siblings born through vaginal delivery — provide very compelling evidence that the association between cesarean birth and childhood obesity is real.

"That's because, in the case of siblings, many of the factors that could potentially be playing a role in obesity risk, including genetics, would be largely the same for each sibling — except for the type of delivery."

Jorge Chavarro PhD

Importance Cesarean birth has been associated with higher risk of obesity in offspring, but previous studies have focused primarily on childhood obesity and have been hampered by limited control for confounders.

Objective To investigate the association between cesarean birth and risk of obesity in offspring.

Design, Setting, and Participants A prospective cohort study was conducted from September 1, 1996, to December 31, 2012, among participants of the Growing Up Today Study, including 22?068 offspring born to 15?271 women, followed up via questionnaire from ages 9 to 14 through ages 20 to 28 years. Data analysis was conducted from October 10, 2015, to June 14, 2016.

Exposure Birth by cesarean delivery.
Main Outcomes and Measures Risk of obesity based on International Obesity Task Force or World Health Organization body mass index cutoffs, depending on age. Secondary outcomes included risks of obesity associated with changes in mode of delivery and differences in risk between siblings whose modes of birth were discordant.

Results Of the 22?068 offspring (20?950 white; 9359 male and 12?709 female), 4921 individuals (22.3%) were born by cesarean delivery. The cumulative risk of obesity through the end of follow-up was 13% among all participants. The adjusted risk ratio for obesity among offspring delivered via cesarean birth vs those delivered via vaginal birth was 1.15 (95% CI, 1.06-1.26; P = .002). This association was stronger among women without known indications for cesarean delivery (adjusted risk ratio, 1.30; 95% CI, 1.09-1.54; P = .004). Offspring delivered via vaginal birth among women who had undergone a previous cesarean delivery had a 31% (95% CI, 17%-47%) lower risk of obesity compared with those born to women with repeated cesarean deliveries. In within-family analysis, individuals born by cesarean delivery had 64% (8%-148%) higher odds of obesity than did their siblings born via vaginal delivery.

Conclusions and Relevance Cesarean birth was associated with offspring obesity after accounting for major confounding factors. Although additional research is needed to clarify the mechanisms underlying this association, clinicians and patients should weigh this risk when considering cesarean delivery in the absence of a clear indication.

Other Harvard Chan authors involved in the study included lead author Changzheng Yuan, Audrey Gaskins, and Matthew Gillman.

Funding for the study came from grants UM1-CA176726, P30-DK046200, U54- CA155626, T32-DK007703-16, HD066963, HL096905, DK084001, and MH087786 from the National Institutes of Health.

"Association Between Cesarean Birth and Risk of Obesity in Offspring in Childhood, Adolescence, and Early Adulthood," Changzheng Yuan, Audrey J. Gaskins, Arianna I. Blaine, Cuilin Zhang, Matthew W. Gillman, Stacey A. Missmer, Alison E. Field, and Jorge E. Chavarro, JAMA Pediatrics, online September 6, 2016, doi: 10.1001/jamapediatrics.2016.2385

Harvard T.H. Chan School of Public Health brings together dedicated experts from many disciplines to educate new generations of global health leaders and produce powerful ideas that improve the lives and health of people everywhere. As a community of leading scientists, educators, and students, we work together to take innovative ideas from the laboratory to people's lives--not only making scientific breakthroughs, but also working to change individual behaviors, public policies, and health care practices. Each year, more than 400 faculty members at Harvard Chan School teach 1,000-plus full-time students from around the world and train thousands more through online and executive education courses. Founded in 1913 as the Harvard-MIT School of Health Officers, the School is recognized as America's oldest professional training program in public health.
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Sep 27, 2016   Fetal Timeline   Maternal Timeline   News   News Archive   

Nurse preparing patient for a cesarean birth.
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