Chavarro JE, et al. JAMA Netw Open. 2020;doi:10.1001/jamanetworkopen.2020.2605.
April 14, 2020
Women born via cesarean delivery were 46% more likely to develop type 2 diabetes and 11% more likely to have obesity during adulthood compared with women delivered vaginally, according to findings published in JAMA Network Open.
“The results of our study suggest that the previously identified relation between birth by cesarean delivery and childhood obesity may extend into adulthood and to health conditions related to obesity that are primarily observed during adult life, such as type 2 diabetes,” Jorge E. Chavarro, MD, ScD, associate professor of nutrition, epidemiology and medicine at Harvard School of Public Health and Harvard Medical School, told Healio. “In other words, it is not just childhood obesity — it may be much bigger than that.”
In a prospective study, Chavarro and colleagues analyzed data from 33,226 women born between 1946 and 1964 who participated in the Nurses’ Health Study II, with follow-up through the end of the 2013-2015 cycle (mean baseline age, 34 years). Participants’ mothers provided information on mode of delivery and pregnancy characteristics; participants provided information on weight and type 2 diabetes status every 2 years. Researchers used Cox proportional hazard regression models to estimate RRs for obesity and type 2 diabetes in women born vaginally vs. cesarean delivery, adjusting for maternal BMI and other factors.
Future risks with cesarean delivery
Women born via cesarean delivery were 46% more likely to develop type 2 diabetes and 11% more likely to have obesity during adulthood compared with women delivered vaginally.
Within the cohort, 1,089 (3.3%) of women were born by cesarean delivery. After 1,913,978 person-years of follow-up, researchers found that 36.6% of women had obesity and 6.1% received a diagnosis of type 2 diabetes.
Researchers found that women born by cesarean delivery were more likely to be classified as obese compared with women born vaginally, with an RR or 1.11 (95% CI, 1.03-1.19). The adjusted HR for type 2 diabetes among women born by cesarean vs. vaginal delivery was 1.46 (95% CI, 1.18-1.81), with the association persisting after further adjustment for the participant’s own BMI (RR = 1.34; 95%CI, 1.08-1.67). Adjustment for breastfeeding did not change the association. Results persisted in analyses restricted to women at low risk for cesarean delivery based on maternal characteristics.
“Findings were consistent across multiple strategies to account for confounding, suggesting that these associations are consistent with a true biological association of birth by cesarean delivery,” the researchers wrote. “Whether these findings are applicable to men or to individuals born today, when cesarean delivery rates are substantially higher, is uncertain.”
More to learn
In an interview, Chavarro noted that the U.S., the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine already advocate for the prevention of primary cesarean deliveries as a means to reduce the overall cesarean delivery rate.
“The results of our study highlight the need to be even more vigilant about decreasing the overall rate of cesarean deliveries, especially in the absence of a clear obstetric or medical indication, as adverse health effects on the offspring could even manifest decades later,” he said.
Chavarro said there is still much to know about how being born by cesarean delivery may affect health over the life course.
“To start with, I would like to see other studies trying to replicate these findings before moving myself from the ‘intrigued by these findings’ to ‘confident that this association is true’ state of mind,” Chavarro said. “Also, even if there is consistent replication of these and similar findings, understanding what the biological underpinnings of this association will be crucial. Our group is actively working on these two fronts and I hope others will follow suit.” – by Regina Schaffer
For more information:
Jorge E. Chavarro, MD, ScD, can be reached at the Harvard T.H. Chan School of Public Health, 655 Huntington Ave., Building II, Third Floor, Boston, MA 02115; email: jchavarr@hsph.harvard.edu.
Disclosures: One of the study authors reports he has received ad hoc consultant fees from Emavant Solutions GmbH. Chavarro reports no relevant financial disclosures.