Using newborns as a long-term gauge for maternal cardiac health may seem like a far-fetched idea, but a new study from investigators at McGill University and the University of Montreal Hospital Research Center has found that women who give birth to infants with congenital heart defects may have an increased risk of cardiovascular hospitalizations later in life. Findings from the new study were released today in the journal Circulation, in an article entitled “Long-Term Risk of Cardiovascular Disease in Women Who Have Had Infants With Heart Defects.”
The new study, which looked at more than one million women, is the first to show congenital heart defects in newborns may be a marker for an increased risk of their mothers developing heart problems, including heart attack and heart failure, years after pregnancy.
"Caring for infants with critical heart defects is associated with psychosocial and financial stress, which may increase the mothers' long-term risk for cardiovascular disease," explained lead study investigator Nathalie Auger, M.D., an epidemiologist at the University of Montreal Hospital Research Centre.
The researchers analyzed data on women who delivered infants between 1989 and 2013 in Quebec, Canada, and who had critical, noncritical, or no heart defects. They tracked the women up to 25 years after pregnancy for hospitalizations related to cardiovascular disease, including heart attack, heart failure, atherosclerotic disorders, and heart transplants.
“We studied a cohort of 1,084,251…and identified women whose infants had critical, noncritical, or no heart defects, and tracked the women over time for future hospitalizations for cardiovascular disease, with follow-up extending up to 25 years past pregnancy,” the authors wrote. “We calculated the incidence of cardiovascular hospitalization per 1000 person-years and used Cox proportional hazards regression to estimate hazard ratios and 95% confidence intervals (CIs) for the association between infant heart defects and risk of maternal cardiovascular hospitalization. Models were adjusted for age, parity, preeclampsia, comorbidity, material deprivation, and time period.”
When the research team compared mothers of infants without congenital heart defects to those with cardiac issues, they found a 43% higher risk of any cardiovascular hospitalization in women whose offspring had critical heart defects. Additionally, the scientists saw a 24% higher risk of any cardiovascular hospitalization in women whose infants had noncritical defects.
How heart defects in infants relate to post-pregnancy cardiovascular disease in their mothers is currently unclear, the study notes, and a genetic component cannot be excluded. Also, because 85% of infants with heart defects now survive past adolescence, the psychosocial impact of congenital heart disease on caregivers may have a cumulative effect over the long term.
The researchers believe the study provides an opportunity for these mothers to benefit from early prevention strategies and counseling to reduce their risk of cardiovascular disease—the leading cause of death in women. However, some limitations of the research include the fact that women were young at the start of the study, so for many, the 25-year follow-up did not extend past menopause, which excluded the highest risk period for cardiovascular disease. Moreover, because researchers used existing medical data, they didn't have detailed risk factor information on the women, such as body weight and smoking status. These are important points that should be considered in future studies, researchers noted.
Yet, healthcare providers, like obstetricians, who treat and follow mothers in the early stages of dealing with children who have heart defects can help women understand and minimize their risk
"Those physicians are very well-positioned to inform women about this possibility, the greater risk of heart disease, and to provide recommendations for targeting other risk factors like smoking, obesity, and physical activity," Dr. Auger concluded.