Pre-eclampsia, a frequent complication of pregnancy characterized by high blood pressure and protein in the urine, is associated with an increased risk for heart defects in newborns, a large study has found.
Canadian researchers studied records of all live births in hospitals in Quebec from 1989 to 2012, a total of 1,942,072 newborns. The study, in JAMA, found an overall prevalence of heart defects of 8.9 per 1,000 births.
But the rate among women with pre-eclampsia was 16.7 per 1,000. Defects in the septums, the walls that separate the heart’s chambers, were the most common, but all parts of the heart were affected — the aorta, pulmonary artery, valves and ventricles. The association was present after controlling for age of the mother, pre-existing hypertension, tobacco use, diabetes, obesity and other factors. Women whose pre-eclampsia occurred earlier in pregnancy were at higher risk.
Pre-eclampsia by definition is diagnosed only after 20 weeks of pregnancy, but the researchers write that pre-eclampsia and heart defects probably share common risk factors that start earlier.
The lead author, Dr. Nathalie Auger, an epidemiologist at the University of Montreal Hospital Research Centre, said obesity is a risk factor for pre-eclampsia, but there is currently no way to prevent pre-eclampsia or heart defects.
“But heart defects are rare,” she added, “and most women with pre-eclampsia will have children with normal hearts.”