For expecting moms, temporary pregnancy-related conditions high blood pressure or diabetes can leave a mark on blood vessels in the brain. New research links these conditions to a higher risk of developing vascular dementia 15 or more years later.
Until a few decades ago, most scientific research and clinical drug trials were done in men. That means that, even though certain differences between men and women might cause disease risk or progression to be different in one sex or the other, those differences weren’t studied. Still today, scientists don’t have a solid understanding of why to some diseases disproportionately affect women: for example, Alzheimer’s.
It’s not yet know why biological females are two times more likely to develop Alzheimer’s in their lifetimes than biological males, but research continues to amass on the links between brain health issues — like Alzheimer’s, dementia, and cognitive decline — and factors specific to females, including hormones, pregnancies and menopause.
For example, the hormone estrogen is found in a higher amount in women than in men. It acts as an important signaling molecule in the brain, and research shows that it may be important for memory and cognition, observing that during menopause, when estrogen levels drop, some women develop brain fog or “menopause brain.”
Pregnancy also brings about these fluctuations in hormonal levels — along with other physiological changes, like transient fluctuations in blood pressure and metabolic function.Researchers at the Alzheimer’s Association International Conference this summer presented strong evidence linking these temporary conditions — high blood pressure during pregnancy and a temporary type of diabetes that occurs during pregnancy, called gestational diabetes — to damage of the brain’s blood vessels and increased risk of vascular dementia.
Vascular dementia occurs as a result of damage to the small blood vessels that bring oxygen and energy to the brain, starving and killing neurons.
“This is among the first longitudinal data linking hypertensive disorders of pregnancy with dementia in a large study cohort,” Claire Sexton, senior director of scientific programs and outreach at the Alzheimer’s Association, said in a statement. “Considering the serious short- and long-term implications of hypertensive disorders of pregnancy, early detection and treatment are vital to protect both the pregnant person and baby.”
The link between pregnancy, hypertension and diabetes, and later-in-life dementia risk
Biological and hormonal changes during pregnancy can lead to the development of different temporary health conditions. Pregnancy may act like a “stress test” on the body and brain, providing a brief window into future risks.
Some of these are related to blood pressure. For example, eclampsia is a condition where the blood pressure spikes high enough to cause seizures. Pre-eclampsia, a less severe form of the same condition, can occur about 20 weeks into gestation, raising blood pressure. A 2018 study published in The British Journal of Medicine found that women who developed preeclampsia during pregnancy had more than tripled their risk of being diagnosed with vascular dementia later in life.
Pregnancy can sometimes also bring about a temporary form of diabetes.
Building on the previous research, Karen Schliep, assistant professor at the University of Utah Health, analyzed data from around 60,000 women who had at least one pregnancy. The presence of pre-eclampsia or eclampsia increased the risk of all-cause dementia by 38 percent. Meanwhile, gestational diabetes increased the risk 36 percent, compared to women who did not develop these disorders during pregnancy.
Women with gestational diabetes had nearly triple the risk of developing vascular dementia.
“Our results confirm previous findings that preeclampsia is most strongly associated with vascular dementia compared to Alzheimer’s or other types of dementia,” said Schliep. “They further suggest that vascular dementia risk may be just as high for women with a history of gestational hypertension as for preeclampsia.”
Another study presented at the conference further strengthened these links. Research led by Rowina Hussainali, a doctoral student from Erasmus MC Medical Center, looked at data gathered from 538 women and found that 15 years after giving birth, women with a hypertensive disorder had 38 percent more white matter pathology — wear and tear of brain tissue — compared to controls.
Women with gestational diabetes had 48 percent more white matter pathology than the controls.
A final study compared 40 women with preeclampsia to 40 healthy controls, finding higher amounts of beta-amyloid in extracellular vesicles — think Amazon packages for cells — sent from cells located near the brain’s blood vessels. Women with severe preeclampsia had more beta-amyloid than women with mild preeclampsia. Inside these vesicles were other signs of neurovascular damage, a risk factor for future development of dementia.
“These findings indicate that women with a history of preeclampsia have increased levels of markers of neurovascular damage which may negatively impact their cognitive skills,” said Mayo Clinic assistant professor of medicine Dr. Sonja Suvakov, who led the study. “Further research is required to fully understand the neurodegenerative and cognitive risks that a history of hypertensive disorders confers on women throughout life.”