Study Links Planned Cesarean Sections to Increased Risk of Childhood Leukemia

Research from Sweden indicates that children born via planned cesarean sections are 21% more likely to develop acute lymphoblastic leukemia (ALL), a type of cancer affecting younger individuals, compared to those delivered vaginally.

This study aligns with previous findings that have also highlighted a potential connection between C-sections and the risk of pediatric ALL. Interestingly, the recent research has pointed to planned cesarean sections specifically as a significant factor. In this context, planned C-sections are those performed before labor begins.

However, the overall risk of ALL, and childhood cancers in general, remains low, as noted by Joseph Wiemels, a professor of public health sciences at the University of Southern California, who was not part of this study. In the United States, approximately 4.8 out of 100,000 children are diagnosed with leukemia each year. While the “relative risk [for ALL] is significantly higher” among those born via planned C-section, Wiemels emphasized that the absolute risk is “still relatively low.”

Christina Evmorfia-Kampitsi, the lead author and a postdoctoral researcher at Karolinska Institutet, stressed that C-sections can be critical and even life-saving procedures. Sometimes, these are performed due to specific maternal conditions like preeclampsia or for the benefit of the baby’s health when there are oxygen supply concerns.

“Our findings should not raise alarms when the procedure is medically indicated,” Evmorfia-Kampitsi remarked.

Further Insights into the Findings

The research, published on July 4 in the International Journal of Cancer, is notable for its thorough analysis. Researchers accounted for numerous maternal and neonatal characteristics while still uncovering a higher risk for ALL among children born via planned cesarean.

Thanks to extensive data from Sweden, the team was able to consider various maternal and newborn factors, strengthening the case that the observed association isn’t merely a result of pre-existing conditions that led to the cesarean in the first place, according to Evmorfia-Kampitsi. Wiemels pointed out that maternal age is also a significant factor, as mothers over 35 may have a higher likelihood of their children developing ALL.

In the study, over 2.4 million births in Sweden were analyzed, focusing on the delivery method—vaginal or cesarean (planned or unplanned)—and considering factors like the newborn’s weight, any birth defects, and maternal health conditions. Researchers also noted the frequency of ALL among these children over time.

About 375,000 of the children, roughly 15%, were born by C-section, with approximately 213,000 categorized as planned. Out of the 2.4 million children, only around 1,200, or 0.05%, were diagnosed with ALL.

The data showed that the risk of ALL was greater for children born by any form of C-section compared to vaginal deliveries. Although there was a slight increase in risk for unplanned C-sections, the most significant correlation was found in those who had planned cesareans.

The planned cesarean categories were further divided into “planned” and “acute,” with acute cases indicating immediate medical needs like fetal distress. Interestingly, these acute cases did not seem to correlate with any increase in cancer risk, but it’s worth noting that there were not enough instances to draw solid conclusions.

“These results should be interpreted with caution,” Evmorfia-Kampitsi advised, reaffirming that their main findings indicate an increased risk tied to planned pre-labor C-sections.

Potential Implications

Childhood ALL is predominantly diagnosed in children under five years of age, and the study’s findings were notably significant within this demographic, suggesting a clearer link between planned C-sections and ALL in younger children.

This could potentially teach us something about leukemia risk factors, Wiemels mentioned. Genetic mutations can arise even before birth, leading some children to be born with pre-leukemia cells; however, many of these children do not go on to develop leukemia, as Erin Marcotte, an associate professor, pointed out.

There’s speculation about how these pre-leukemic cells are managed, with two leading theories regarding the role of C-sections. One suggests that babies born this way miss out on beneficial microbes they would typically acquire during vaginal birth, which might create a more hospitable environment for leukemia to develop. The second theory posits that these infants lack exposure to stress hormones present during labor that might help eliminate pre-leukemic cells.

While the connection between C-sections and ALL is noteworthy, Evmorfia-Kampitsi cautioned that the overall risk remains low. Nevertheless, awareness of potential long-term outcomes is crucial, particularly when considering a C-section without a clear medical reason.

Further exploration into the relationship between ALL and planned cesarean deliveries is necessary, as there are regions where higher cesarean rates do not equate to increased leukemia diagnoses. Since this study focused on a Swedish population, it remains uncertain whether findings would replicate in different demographic contexts.