Researchers warn planned C-section births — the most common surgery in the US — can increase risk of childhood cancers

Yahoo

08-07-2025

Children born using planned Cesarean section procedures may have a heightened risk of developing certain childhood cancers, according to the researchers.
After studying the health of nearly 2.5 million children, members of the Swedish Karolinska Institutet found an increased risk of developing acute lymphoblastic leukemia during these events – and not in similar emergency 'C-section' procedures.
They're still working to understand why this is the case, but have identified possible factors that could help to explain. The researchers noted that babies in planned C-sections are not stressed or exposed to vaginal bacteria, as during emergency C-sections. Doctors perform a C-section when the health of the baby is at risk or when a vaginal delivery isn't possible or safe.
'C-sections are an important and often life-saving part of obstetric care. We don't want mothers to feel anxious about medically indicated C-sections. But when this result is combined with other study results showing that the risk of later asthma, allergies or type 1 diabetes increases in children born by planned C-section, there is reason to discuss C-sections that are not medically indicated," researcher Christina-Evmorfia Kampitsi said in a statement.
Kampitsi and her team found that of the nearly 376,000 children born in by C-section Sweden between 1982 to 1989 and 1999 to 2015, nearly 1,500 later developed leukaemia. The risk of acute lymphoblastic leukemia was 21 percent higher in children born by planned C-section compared with children born vaginally.
Furthermore, the risk of developing the most common form of acute lymphoblastic leukemia, known as B-cell acute lymphoblastic leukemia, was 29 percent higher in those born by planned C-section. The increased cancer risk was more pronounced in boys than in girls, and in the early years of a child's life.
Acute lymphoblastic leukemia is a type of blood and bone marrow cancer, and the most common type of cancer in children. It's also unclear what causes the DNA mutations that can lead to the cancer, but treatments result in a good chance for a cure, according to the Mayo Clinic. The American Cancer Society estimates there will be 6,100 new cases and 1,400 deaths this year due to the cancer in both U.S. children and adults.
The researchers emphasized that the risk of developing these cancers remains low, regardless of the mode of delivery.
The excess risk associated with planned C-sections corresponds to approximately one case of B-cell acute lymphoblastic leukemia annually, they said.
C-sections have become increasingly common in the U.S., accounting for about one in three births, according to Centers for Disease Control and Prevention data. Notably, maternal mortality has been rising in the U.S. in recent years, with as many as 84 percent of pregnancy-related deaths believed to be preventable, according to Yale Medicine.
There are 1.2 million C-sections performed every year, making it the 'most common major surgery performed in the United States,' according to Dr. Cindy Celnik, the chief medical officer of The Woman's Hospital of Texas.
"Fortunately, acute lymphoblastic leukemia is rare,' added Kampitsi. 'This means that many C-deliveries are needed to obtain a statistically significant result, and it is difficult to obtain such a large sample in a Swedish registry study. However, the results are close to significant, are in line with what previous studies have shown, and remain when we adjust for other relevant factors, which still makes them relevant.'
Kampitsi was the lead author of the findings, which were published on Friday in The International Journal of Cancer.