Certain pregnancy complications may increase risk of heart disease in women

A new study from the Institute for Clinical Evaluative Sciences (ICES) and St. Michael’s Hospital shows that women who develop certain pregnancy complications may be at higher risk of developing heart disease and stroke after the birth of their baby.

Researchers tracked over one million pregnant women in Ontario who were free from heart disease, and who delivered for the first time between 1990 and 2002. They determined the number of women who developed the pregnancy complications pre-eclampsia (new-onset hypertension in pregnancy after 20 weeks gestational age, in association with protein in the urine), gestational hypertension (new-onset hypertension in pregnancy after 20 weeks gestational age, without associated protein in the urine), placental infarction (blockage of blood circulation to a localized area of the placenta), or placental abruption (the premature separation of the placenta from the uterine wall), around the time of delivery.

The investigators then examined whether women who developed one of these pregnancy complications – known as maternal placental syndromes – developed heart disease and stroke, compared to women whose pregnancy was free of these complications.

The results showed that the incidence of heart disease doubled for women with a maternal placental syndrome, compared with women who had no such complication. This risk was further increased in women who also had poor fetal growth or death of the fetus while in the womb, and in women with pre-existing risk factors for heart disease, such as smoking, hypertension, diabetes, obesity, and high cholesterol.

“Our study highlights just how much a woman’s health before, as well as during, her pregnancy can affect her risk of developing heart disease later on,” said lead author Dr. Joel Ray, a clinician scientist at St. Michael’s Hospital and the University of Toronto.

“Because the risk is similar to conventional heart disease risk factors, such as pre-pregnancy hypertension, obesity, diabetes, and high cholesterol, we believe that maternal placental syndrome should be considered an additional risk factor for heart disease.”

Dr. Ray cautions, however, that it is not known whether the same sorts of metabolic or lifestyle modifications that are recommended for people with traditional heart disease risk factors can prevent maternal placental syndromes.

“Nevertheless, we should try and ensure that women are at a healthy weight and avoid smoking before they enter their reproductive years. As well, women who do develop a maternal placental syndrome should be checked following the birth of their baby to ensure that they are maintaining a healthy weight and blood pressure,” he said.

The study, “Cardiovascular health after maternal placental syndromes (CHAMPS): population-based retrospective cohort study”, is in the November 19, 2005 issue of The Lancet.

Author affiliations: ICES (Drs. Schull, Vermeulen and Redelmeier); Department of Medicine (Drs. Ray, Schull, Vermeulen and Redelmeier), and Department of Health Policy (Drs. Ray, Schull and Redelmeier), University of Toronto; and Departments of Medicine and Obstetrics and Gynecology, St. Michael’s Hospital (Dr. Ray)

ICES is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy.

St. Michael's Hospital is a large and vibrant Catholic teaching and research hospital in the heart of Toronto. Fully affiliated with the University of Toronto, St. Michael's Hospital leads with innovation, and serves with compassion. Renowned for providing exceptional patient care, St. Michael's Hospital is a regional trauma centre and downtown Toronto's designated trauma centre for adults. For more information, please visit www.stmichaelshospital.com.

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