Jorge Wong - leading scientist
Women who have multiple pregnancies are at a greater risk of developing an irregular heartbeat, according to new research led by a McMaster University researcher.
The study, published in the American Heart Association's journal, Circulation, links the number of pregnancies to a type of irregular heart rhythm called atrial fibrillation.
Scientists led by Jorge Wong, a researcher with McMaster's Population Health Research Institute, analyzed data from 34,639 participants in the Women's Health Study.
The participants had a median of two prior pregnancies and were healthy at the start of the study. After an average of 20 years of follow-up, 1,532 cases of atrial fibrillation had occurred.
"We found that an increase in the number of pregnancies was associated with a higher risk of future atrial fibrillation," said Wong. "For example, women with four or more pregnancies were approximately 30 to 50 per cent more likely to develop atrial fibrillation compared to women with no pregnancies."
Atrial fibrillation can lead to blood clots, stroke, heart failure and other heart-related complications. Repeated exposure to physiological, metabolic or hormonal factors during pregnancy may be the reason for the link, the researchers said.
"The point here is not to discourage women from having children," Wong said. "However, our research highlights that something about pregnancy predisposes women to this greater risk, and more research is needed to help us understand why."
Women in the study were primarily of European descent, so the results may not apply to women of all ethnicities.
The co-author of the study was Dr. Christine Albert, a Harvard Medical School professor and director of the Center for Arrhythmia Prevention at Brigham and Women's Hospital where the Women's Health Study is based.
The research was supported the U.S. National Heart, Lung and Blood Institute, the U.S. National Cancer Institute, the Canadian Institutes for Health Research and the Arthur J.E. Child Cardiology Fellowship.