Preeclampsia—a spike in blood pressure that only occurs during pregnancy or the postpartum period, can be a scary complication of giving birth—in fact, it can lead to strokes and seizures, and even to death, accounting for about 8 percent of maternal deaths in the U.S. each year. Now, a new study points out that people who experienced preeclampsia have a continued risk much after the initial danger passes, finding that the condition triples the likelihood of dementia.
The large study published in The BMJ looked at 1.1 million women in Denmark who gave birth from the years 1978 to 2015. No one had been diagnosed with vascular problems like stroke, diabetes or dementia before giving birth. They found that those with a history of preeclampsia were 3.4 times more likely to be diagnosed with vascular dementia— at type of brain disease characterized by a blockage in the blood vessels that lead to the brain, resulting in a lack of blood supply and oxygen. Preeclampsia was not found to have a strong association with Alzheimer’s or other types of dementia.
Preeclampsia is not uncommon. Around the world, approximately five women per hour die from it. But in developed countries, systems have been put in place to catch it. Britain, for example, has very few preeclampsia deaths—literally one in a million. The U.S. lags behind, with between 50 and 70 deaths per year.
In an accompanying editorial, Joel Ray, M.D., a professor of medicine at the University of Toronto, said that the association makes sense, as preeclampsia and vascular dementia are both “propagated by pre-existing cardiovascular risk factors and have a pathogenesis that targets blood vessels.”
The study authors said knowing about this possible link could help doctors know which women to screen for early prevention methods for vascular dementia, like controlling blood pressure and monitoring cholesterol.
This study joins a growing body of research that is examining the connection between pregnancy and dementia later in life. Other research shows that having a stroke doubles the chances of dementia and that having even slightly higher blood pressure in mid-life significantly raises the risk of dementia later. Clearly, the link between vascular health and brain health is strong. But the good news is that it’s one risk factor that might be modifiable.
According to Ray, vascular dementia “might be preventable in women with previous pre-eclampsia, with good control of blood pressure, lipids, and glucose.”
Still the association is just that—it’s not enough evidence to say whether preeclampsia actually causes dementia later in life.