Preeclampsia is a serious condition that can occur in the last weeks of pregnancy. It is characterized by high blood pressure and high levels of protein in the urine. A recent large study has found that pre-eclampsia is associated with an increased risk for heart defects in newborns.
In this study, researchers studied the records of all live births that occurred in hospitals in the Province of Quebec from 1989 to 2012, a total of 1,942,072 births. There were 8.9 babies with heart defects for every 1,000 births, overall.
However, the rate of birth defects among women with preeclampsia was 16.7 babies with heart defects per 1,000 babies born. This is an increase in the rate of this type of defect, but a birth defect of the heart is still a rate event, the study noted.
The most common type of heart defect were defects in the septums, the walls that separate the heart's chambers, but defects were seen in all parts of the heart including the aorta, pulmonary artery, heart valves, and ventricles. More serious defects of the heart occurred in babies born to mothers with preeclampsia diagnosed before the thirty-fourth week of pregnancy.
This association between preeclampsia and heart defects was seen even after the researchers controlled for the age of the mother, pre-existing hypertension, tobacco use, diabetes, obesity, and other factors. Women whose preeclampsia occurred earlier in pregnancy were at higher risk than those in whom it occurred later.
By definition, preeclampsia 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 in the pregnancy. One of the risk factors for preeclampsia is obesity, but there is currently no way to prevent pre-eclampsia.
The study was conducted at the National Institute for Public Health of Quebec and the University of Montreal. It was published in The Journal of the American Medical Association.