The study is the first to show a protective benefit of having a vaginal delivery after a prior cesarean birth.
A new study in JAMA Pediatrics finds there is a risk associated between cesarean births and obesity in the children, after accounting for other factors.
Researchers at the Harvard T.H. Chan School of Public Health examined data from the Growing Up Today Study (GUTS), a large prospective cohort that has followed more than 22,000 people from childhood to early adulthood for 20 years, since September 1996.
Among all participants, more than one-fifth (22.3%) were born by cesarean delivery, and the cumulative risk of obesity through the end of follow-up was 13%. The women who underwent cesarean delivery had a higher body mass index (BMI) before pregnancy and were more likely to have gestational diabetes, pre-eclampsia, and pregnancy-induced hypertension. They were also more likely to have had a prior cesarean delivery.
The researchers found that those born by cesarean delivery were 15% more likely to become obese than those born by vaginal delivery, and those born by cesarean delivery had 64% higher odds of obesity compared with siblings born by vaginal delivery. Vaginal delivery after cesarean delivery was associated with a 31% lower risk of future obesity, compared with those born by a repeat cesarean delivery. The authors report this is the first time this effect has been observed.
Thus, the study suggests the importance of strategies to reduce the number of unnecessary cesarean deliveries in hospitals, not only for the immediate risks they create but, apparently, for the future health of the child. While not all cesarean births can be avoided, some should be.
“The association between between cesarean birth and obesity in offspring was stronger in analyses restricted to individuals without known risk factors for cesarean delivery and in within family analyses,” the authors write. “These findings suggest that that this association may be a true adverse outcome of cesarean birth in the absence of a clear medical or obstetric indication.”
Rates of cesarean delivery were highest from 1985 to 1989 and fell afterward, when increased attention to the costs and risks of this practice caused hospitals and medical professionals to turn their attention to reducing the rates of cesearean deliveries. Among the strategies that have been pursued is working with pregnant women who had previously had a cesarean delivery to not assume that a vaginal delivery in the future is impossible.
Yuan C, Gaskins AJ, Blaine AI, et al. Association between cesarean birth and risk of obesity in offspring in childhood, adolescence and early adulthood [published online September 6, 2016]. JAMA Pediatr. 2016; doi:10.1001/jamapediatric.2016.2395.