Photo by Nina Matthews
Researchers have found a potential correlation between pre-labor cesarean delivery (PLCD) and acute lymphoblastic leukemia (ALL).
The team analyzed data from 13 studies and found a 23% increase in the risk of ALL in children born by PLCD.
However, there was no link between PLCD and acute myeloid leukemia (AML), and there was no correlation between emergency cesareans and ALL or AML.
Erin Marcotte, PhD, of the University of Minnesota, and her colleagues reported these results in The Lancet Haematology.
The researchers analyzed data from the Childhood Leukemia International Consortium. They looked at 33,571 subjects overall, including 23,351 control subjects, 8780 cases of ALL, and 1332 cases of AML.
The analyses were controlled for a number of outside factors, including breastfeeding, parental education levels, and ethnicity.
“Our goal was to determine if there was an association between cesarean deliveries and ALL [and] to identify potential new targets for research into cancer prevention if there is a correlation,” Dr Marcotte said.
“While the link between overall cesarean delivery and childhood leukemia was not statistically significant, it was notable to find an association between pre-labor cesarean delivery and ALL.”
The data suggested AML was not associated with cesarean delivery. The odds ratios (ORs) were 0.99 for all cesarean deliveries, 0.83 for PLCD, and 1.05 for emergency cesarean delivery.
The ORs for ALL were 1.06 overall, 1.02 for emergency cesarean delivery, and 1.23 (P=0.018) for PLCD.
The reason for the increased risk of ALL with PLCD is not known. The researchers said several mechanisms may be at play, including the stress response in the fetus caused by labor and the colonization of microbiota a newborn experiences during a vaginal delivery that is missed during a cesarean birth.
“The most plausible explanation for the association between ALL and pre-labor cesarean delivery is in the cortisol, or stress-related, mechanism,” Dr Marcotte said. “Because ALL is not associated with all cesarean deliveries, it seems less likely the microbiota colonization is a significant factor in this phenomenon. We believe further investigation into this cortisol-mechanism link is warranted due to these findings.”
The researchers said the strength of association in these findings is comparable to other studies looking at cesarean delivery rates and other childhood outcomes, including Type I diabetes and asthma. They believe further investigation into this study’s findings is needed, utilizing more detailed and reliable delivery information.
“This association deserves a closer look to better determine what’s behind the link,” said Logan Spector, PhD, of the University of Minnesota.
“Cortisol exposure is plausible since similar compounds are used to treat ALL. We also know that some are born with cells that are on the path to becoming leukemia. Thus, our working hypothesis is that cortisol exposure at birth may eliminate these pre-leukemic cells.”
