Pregnant women with placental disorders have higher heart disease risk: study

TORONTO (CP) - Women who develop placental complications during pregnancy appear to have an elevated risk for heart attack, stroke and other cardiovascular-related events in the years after the birth of their baby, a Canadian study suggests.

In fact, the study found that a woman's risk of premature cardiovascular disease doubled if she had one of several disorders involving the placenta, including pre-eclampsia, gestational high blood pressure and separation of the placenta from the uterine wall.

The threat of suffering a heart attack, stroke or other critical condition that required hospitalization was even higher if a baby's growth during gestation was poor or the fetus died in the womb, said lead investigator Dr. Joel Ray, a specialist in obstetrical medicine at St. Michael's Hospital in Toronto.

"And the time to that incident event from their pregnancy to the point after was only about 8 1/2 years, so that the window to the subsequent event is relatively short," Ray said.

The researchers analysed the health records of more than one million women in Ontario after the birth of their first child between 1990 and 2004, using a database compiled by the Institute for Clinical Evaluative Sciences. None of the women had been diagnosed with cardiovascular disease before pregnancy.

The study, published in Friday's edition of The Lancet, found that 75,000 of the women had experienced maternal placental syndrome; within less than nine years on average, 305 of them had a heart attack, unstable angina, stroke, peripheral artery disease (affecting the arteries of the legs) or needed such procedures as coronary bypass or angioplasty to open up blocked arteries.

But it is not the placental disorders themselves that cause these conditions to develop, Ray theorized.

"The notion here is that there would be a common mechanism that we believe would link an event that would happen in pregnancy to an event that would happen after pregnancy, a cardiovascular event, in other words," he said.

"So it's not that a woman got pre-eclampsia that makes her get heart disease or stroke, but that it's her metabolic state prior to pregnancy, during pregnancy and after pregnancy that predisposes her to both maternal placental syndrome and cardiovascular disease."

Ray said a predisposition could exist for obesity, diabetes, elevated cholesterol and high blood pressure - all conditions linked to heart disease and stroke.

"A woman who had such a problem would have it at age 12, at age 25, age 30 and age 40 or 50," he said. "Just as she has the same skin colour or the same family history or the same genetic code, she would also have a tendency to a certain kind of metabolism and those components carry forward.

"So that when she enters pregnancy, they're similarly present and they contribute to the abnormal development of the arteries of the placenta."

Data showed that the average age when a woman gave birth for the first time was 28; a serious cardiovascular event occurred on average at age 38. None of the women hospitalized was over 60.

"So these are very premature cardiovascular events," Ray said, adding that his research team did not look at deaths among the women nor subsequent pregnancies.

The researchers say doctors should check new mothers who had placental disorders six months after delivery, looking for signs of cardiovascular disease by using even simple measures like blood pressure and abdominal circumference as an indicator of obesity.

"If they are overweight, it provides an opportunity for them to realize that their overweight state has implications ... for cardiovascular disease risk," said Ray, advising that the women should be encouraged to eat a nutritionally balanced diet and get regular exercise by walking 30 minutes a day.

"The beauty is that although a woman can't change her genetics or her family history, she can alter her health in advance of a pregnancy and after a pregnancy that's been affected by a maternal placental syndrome."