Does high blood pressure in pregnancy raise dementia risk?
Yes, but mostly through the blood pressure and heart problems that tend to follow it. In a study of 1.37 million Korean women, those who had high blood pressure in pregnancy had nearly double the risk of dementia about two decades later. Once researchers accounted for high blood pressure, diabetes, heart attack, and stroke that showed up after delivery, the extra risk mostly disappeared.
High blood pressure in pregnancy covers a group of conditions: gestational hypertension, preeclampsia, HELLP syndrome (red blood cell breakdown, elevated liver enzymes, and a low platelet count), and eclampsia. Doctors already know these conditions mark a woman for more heart disease later in life. Whether they also mark her brain has been less clear. This study, published in JAMA Network Open, tracked women who gave birth in South Korea between 2002 and 2005 and followed them through the end of 2024.
What the data show
Of 1,370,485 women, 28,747 (2.1%) had high blood pressure in pregnancy. Their average age at delivery was about 29. Over follow-up, 7.2 of every 10,000 women with a pregnancy blood pressure disorder developed dementia, compared with 2.8 of every 10,000 women without one. That is about 4 extra cases for every 10,000 women. There is less than a 1 in 1,000 chance that gap is a coincidence.
After adjusting for the mother’s background, social and economic factors, and pregnancy details, women with high blood pressure in pregnancy still had about 96% higher risk of dementia (hazard ratio 1.96). The researchers are 95% confident the true increase falls somewhere between 19% and 223% higher, a wide range that reflects how few cases there were.
The second analysis tells the more useful story. When the researchers also accounted for high blood pressure, diabetes, heart attack, and stroke that developed after delivery, the extra risk shrank to about 15% (hazard ratio 1.15) and was no longer statistically significant. The true effect could plausibly be anywhere from 30% lower to 91% higher.
Dr. Kumar’s Take
This is the finding that matters: the pregnancy itself does not seem to be what harms the brain. The risk appears to travel through vascular disease that builds up in the years afterward. Chronic high blood pressure, diabetes, heart attack, and stroke are all things we can detect and treat long before memory starts to slip.
The brain runs on a steady blood supply. Anything that stiffens or damages small blood vessels over decades can take a toll on thinking. A pregnancy with high blood pressure may be an early warning that a woman’s blood vessels are more vulnerable, which is how the authors frame it: a marker of long-term brain and blood vessel risk.
The absolute numbers are small. Most women in this study were only around 50 by the end of follow-up, which is young for dementia. The bigger payoff may come later, as these women reach the ages when dementia becomes common.
How strong is the evidence?
The size is impressive. It drew on Korea’s nationwide health insurance database, included women 16 or older who gave birth over a four-year span, and followed women for about two decades. That reduces the chance of cherry-picked patients.
The weak point is the number of dementia cases. The authors say themselves that the small number of events among women with pregnancy blood pressure disorders means the findings “should be interpreted cautiously.” That is why the confidence ranges are so wide.
This was also an observational study. It shows a link, not proof of cause. Insurance records depend on diagnosis codes, and the study was done in one country, so results may not transfer exactly to other populations.
Practical Takeaways
- If you had preeclampsia, gestational hypertension, HELLP, or eclampsia, tell every doctor you see, since this history is easy to forget decades after the birth.
- Keep up with regular checkups in the years after a high-risk pregnancy. The researchers found that stroke, more than diabetes or later high blood pressure, may play a particularly important role in the link to dementia.
- Treat high blood pressure and diabetes seriously if they develop, since protecting your blood vessels likely protects your brain too.
- Keep the absolute risk in view: the extra dementia cases in this study were about 4 per 10,000 women.
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FAQs
Does preeclampsia cause dementia?
This study does not show that preeclampsia causes dementia. It found a link that mostly faded once later high blood pressure, diabetes, heart attack, and stroke were taken into account. That pattern points to the vascular problems that follow, rather than the pregnancy itself. Preeclampsia is better thought of as an early signal worth acting on.
If my blood pressure went back to normal after delivery, am I still at risk?
For many women, blood pressure returns to normal after the baby is born. The concern is what happens over the following years, since a pregnancy blood pressure disorder is a known marker for heart disease later in life. Normal readings right after delivery are reassuring, but they do not replace ongoing checks. Blood pressure can creep up slowly without symptoms.
Is gestational hypertension the same as preeclampsia?
No. Gestational hypertension is high blood pressure that starts during pregnancy. Preeclampsia, HELLP syndrome, and eclampsia are separate conditions in the same family. This study reported dementia rates for each type, but so few women in each group developed dementia that those comparisons are only exploratory. HELLP syndrome was too rare to report on its own.
Bottom Line
Women who had high blood pressure in pregnancy had nearly twice the risk of dementia about 20 years later, though the absolute increase was small, about 4 extra cases per 10,000 women. The link largely disappeared once later high blood pressure, diabetes, heart attack, and stroke were accounted for. That makes a high-risk pregnancy a useful early warning, and it points to blood pressure and blood sugar control in the decades afterward as the place where prevention likely happens.
