Congenital heart defects may be linked to increased cancer risk in babies and mothers

Being born with a heart defect may be associated with an increased cancer risk for babies and their moms, according to new research published today in the American Heart Association’s flagship journal Circulation.

According to the American Heart Association, the most common birth defects in the U.S. are forms of congenital heart defects (CHD). They range from structural abnormalities, such as openings between the heart’s chambers, to severe malformations, such as the absence of heart chambers or valves. In the U.S., about 12 infants in 1,000 births have a congenital heart defect, according to the Association’s 2025 Heart Disease and Stroke Statistics. While numerous medical advances have enabled children with heart defects to survive longer than they used to, some research suggests they may be at higher risk for developing other conditions including cancer.

Researchers analyzed health information about more than 3.5 million live births from the Korean National Health Insurance Service database from 2005 to 2019. They followed all newborns and mothers for cancer diagnoses for an average of 10 years.

Our research highlights the importance of maternal factors and genetic traits and understanding how they may be connected.”

June Huh, M.D., Ph.D., study author, professor of cardiology in the department of pediatrics at the Heart Vascular Stroke Institute, Samsung Medical Center at Sungkyunkwan University School of Medicine in Seoul, Korea

The findings show that care for congenital heart defects may benefit from including different health care professionals to provide well-rounded care for families, he said.

The analysis found:

• Overall, the incidence of cancer was 66% higher in newborns with congenital heart defects compared to those born without a heart defect.
• Specifically, compared to newborns without congenital heart defects, cancer risk was more than double in newborns with congenital defects that involved blood vessels or heart valves and two times higher among those with complex congenital heart disease. 
• The most common types of cancers that developed among all of the children, both with and without congenital heart defects, were leukemia (21%) and Non-Hodgkin lymphoma (11%).
• Mothers who gave birth to newborns with congenital heart defects were 17% more likely to be diagnosed with cancer in the 10-year follow-up period compared to mothers who gave birth to newborns without a congenital heart defect.

Researchers have yet to determine why having a baby with a congenital heart defect is associated with a higher risk for cancer in mothers. Potential factors include the mother’s genetic predisposition or a mutation known to contribute to cancer and congenital heart defect risks in newborns.

“The genetic variants inherited from the mother may provide the necessary environment for cancer to develop in congenital heart defect patients, highlighting a possible shared genetic pathway underlying both conditions,” Huh said.

American Heart Association volunteer expert Keila N. Lopez, M.D., M.P.H., said the study’s finding of a cancer association among mothers of infants with congenital heart defects was surprising.

“This finding needs to be further explored to understand if there are environmental factors affecting genes (epigenetics) or stress-related changes linking congenital heart defects with maternal cancer risk,” said Lopez, chair of the Association’s Young Hearts Congenital Cardiac Defects Committee and an associate professor of pediatric cardiology at Texas Children’s Hospital, Baylor College of Medicine in Houston. “There is some data that suggests stress is related to cancer risk, and having a child with a congenital heart defect can be very stressful. So having studies that investigate and demonstrate all the links between cancer and congenital heart defects will help us understand lifelong risks of not only heart defects but also the development of cancer within families.”

The study also emphasizes the importance of follow-up care with a pediatric cardiologist and primary care physicians and the need for lifelong care for ongoing surveillance of those born with congenital heart defects, Lopez said.

Study limitations include the possibility that unknown factors may have biased study results, and some analyses lacked power due to a small number of specific types of congenital heart defects. While the study was from data for people in Korea, Huh said the findings may apply to other populations.

Study details, background and design:

• Researchers reviewed health information for more than 3.5 million babies in Korea born with and without congenital heart disease (51.5% boys, 48.5% girls). Of the live births, 72,205 newborns had a congenital heart defect. Mothers (19,310) who had a history of cancer were excluded from the analysis.
• The analysis of the nationwide study was conducted using data from the Korean National Health Insurance Service database from January 1, 2005, to December 31, 2019. Called K-NHIS data, the information included individual-level demographics, and all records of diagnosis and health care (including office visits, prescriptions and medical procedures), as well as provided inpatient, outpatient and emergency department visits.
• For a cancer diagnosis to be counted in this study, the same International Classification of Diseases 10th Revision (ICD-10) cancer code had to appear at least three times within a year in the medical records or result in at least one inpatient hospitalization.
• The analysis was performed in 2024.