By Greg Tartaglione, SIECUS Program Research Intern
Karthik Darmasseelane, Matthew J. Hyde, Shalini Santhakumaran, Chris Gale, Neena Modi, “Mode of Delivery and Offspring Body Mass Index, Overweight and Obesity in Adult Life: A Systematic Review and Meta-Analysis,” PLoS ONE (February 2014)
Researchers from the Imperial College in London reviewed available data from 35 studies that provided data on birth delivery characteristics and the long-term physical health of babies as they grew into adulthood. With evidence that cesarean section (C-section) appears to increase childhood risk of breathing problems, asthma, allergic reactivity, and other developmental issues in comparison to vaginal deliveries, the authors arguethat delivery methods may directly affect risk of obesity in adulthood, among other chronic health concerns.
- The average Body Mass Index (BMI) of adults delivered by C-section was higher than the BMI of those delivered vaginally.
- By adulthood, those born by C-section were 26% more likely to be overweight, and 22% more likely to be clinically obese, than those born by vaginal delivery.
- Findings were not affected by factors such as the biological sex of the infant and pre-labor versus in-labor cesarean delivery. However, the association between C-section and adult obesity was stronger for younger adults born this way than for older adults.
Though the World Health Organization (WHO) has long recommended that nations set a goal of no more than 15% of all births by C-section in any given year, in most countries the percentage continues to rise. This article, from the United Kingdom, notes that England’s percentage of C-sections has doubled from 1990-2008 (to 24% of all births); England’s percentage of clinically obese has risen correspondingly (to 26% of the population, an increase of 10% since 1995). The U.S. has some of the world’s highest percentages of both cesarean delivery and obesity: 33% and 34% respectively.
The authors conclude that the percentage of cesarean sections is rising worldwide, and that the correlation of cesareans with long-term health risks should be studied further, to determine whether it involves additional confounding influences and general trends in physical health and the use of new medical technologies.
There is little consensus in the field of maternal and child health as to what long-term effects delivery by C-section might have on people as they grow into adulthood. Natural childbirth advocates sometimes argue that, in addition to increasing risks for allergies and asthma, cesarean delivery increases infants’ need for special care early on, and extends their time in neo-natal units away from skin-to-skin contact with adults. Others suggest that C-sections result in too-early delivery, or expose babies to anesthesia, in ways that may increase developmental delays.
Though cesarean-enabling technologies have helped to significantly lower childbirth mortality rates in women, the WHO argues that overuse of surgical interventions can negatively affect health outcomes. This may be due to health care providers’ failure to educate women on the full range of viable childbirth options available to them.
Sexuality educators can use the information in this study to help parents-to-be consider the pros and cons of different birthing options, not just as they affect the mother at delivery, but also as they might affect the baby after delivery. As the authors of this article note,
“The possibility of a causal relationship [between C-sections and offspring obesity must] be addressed as a matter of urgency, at the very least to provide the sound evidence required for women to make an informed decision regarding the advisability of delivery by CS in the absence of medical indication.”
 Gibbons L, Belizán JM, Lauer JA, Betrán AP, Merialdi M, Althabe F (2010). The global numbers and costs of additionally needed and unnecessary caesarean sections performed per year: Overuse as a barrier to universal coverage. World Health Report. Accessed July 17, 2014 at http://www.who.int/healthsystems/topics/financing/healthreport/30C-sectioncosts.pdf.
 Gibbons et al, “Global Numbers…”
 Darmasseelane K, Hyde MJ, Santhakumaran S, Gale C, Modi N (2014). Mode of delivery and offspring body mass index, overweight and obesity in adult life: A systematic review and meta-analysis. PLoS ONE 9(2), accessed July 17, 2014 at http://www.plosone.org/article/info:doi/10.1371%2Fjournal.pone.0097827.