2023 Author: Anita Thornton | [email protected]. Last modified: 2023-05-22 03:30
Pregnant women who experience preeclampsia during pregnancy have a higher risk of giving birth to a baby with a congenital heart defect.
A large study of 1.9 million mothers and their newborns by a team from the Center de recherche du Center hospitalier de l'Université de Montréal (CRCHUM) demonstrates for the first time a clear association between these diseases of mother and baby, from the beginning of pregnancy.
This study published on October 21, 2015 in the prestigious journal JAMA, The Journal of the American Medical Association, lays the foundation for future research to improve the prevention and detection of these diseases.
Congenital heart defects are the most common defect in newborns. They affect eight out of a thousand births. Despite medical advances, they are a significant cause of childhood illness and death. “We discovered that congenital heart defects are significantly more frequent when the mother suffered from preeclampsia during her pregnancy,” says Dr. Nathalie Auger, first author of the study, researcher at the CRCHUM andprofessor of social and preventive medicine at the University of Montreal.
Why are some babies born with a heart defect? The origin is sometimes hereditary. But beyond this observation, the causes and risk factors remain unknown. Researchers are investigating the possibility of a link to preeclampsia, a condition in pregnant women characterized by high blood pressure (hypertension) and high protein levels in urine (proteinuria). “Pregnant women affected by preeclampsia and babies born with a heart defect have similarities in the biological factors that are used in the formation of blood vessels. It is this coincidence in the imbalance of angiogenic factors that prompted us to undertake this population study,” explains Dr. Auger.
Researchers examined the registry of all live births in hospitals in Quebec – a quarter of Canada's population – between 1989 and 2012. All women who gave birth after 20 weeks of pregnancy during this period were considered, representing 1,942,072 newborns.
Overall, 17,296 newborns, or 8.9 out of a thousand newborns, have a heart defect. In women who have suffered from preeclampsia, the incidence of heart defects jumps to 16.7 per thousand newborns, compared to 8.6 per thousand for women who were not affectedby preeclampsia. The most frequent malformations of the heart are non-critical damage, such as septal malformations, which manifest themselves by a hole in the wall which separates the two ventricles or the two atria of the heart and causes a blood circulation problem. “The absolute risk of congenital heart defects is low. But there is a real link between preeclampsia and the risk of delivering a baby with a heart defect. And this risk is higher when preeclampsia occurs before 34 weeks of pregnancy,” notes Nathalie Auger.
Preeclampsia is detectable from the 20th week of pregnancy. This complication can sometimes progress to a frank eclampsia endangering the life of the mother and the baby in the most serious cases. In fact, the biomarkers that prevent the formation of blood vessels are present from the start of pregnancy in the woman who will later develop the disease. The baby's heart is formed at the beginning of intrauterine life. If a heart defect occurs, it usually occurs between eight and ten weeks of gestation. "There is possibly a common factor in the embryo and the mother that triggers both preeclampsia and heart defects very early in pregnancy," says the epidemiologist.
Currently, a woman diagnosed with preeclampsia is closely monitored to see if the baby is developing normally. Most babies with a malformationcongenital heart disease can be saved. They are treated with drugs, non-invasive procedures or surgery. “Further research is needed before changing medical recommendations. But knowing that preeclampsia can increase the risk of congenital heart defects in the unborn baby should help to better understand the pathophysiology of these diseases and ultimately improve their prevention and treatment,” concludes Dr. Auger.
About this study
The Association Between Preeclampsia and Congenital Heart Defects study was published online in JAMA, The Journal of the American Medical Association, on October 20. The Canadian Institutes of He alth Research (CIHR) funded this research (MOP-130452) and Dr. Nathalie Auger holds a salary award from the Fonds de recherche du Québec – Santé (FRQS) (grant 25128). The authors state that the granting agencies had no involvement in the research protocol or the publication of the results. Find out more.
About the CRCHUM
The Research Center of the Center hospitalier de l'Université de Montréal (CRCHUM) improves he alth in adults through a continuum of high-level university research which, in improving the understanding of etiological and pathogenic mechanisms, promotes the development, implementation and evaluation of new preventive, diagnostic and therapeutic strategies. The CRCHUM offers atraining environment ensuring a succession committed to a quest for excellence.
Source: University of Montreal Hospital Center Research Center (CRCHUM)