Low-dose aspirin, one of the cheapest and most widely available medications on the planet, is the drug that lowers the risk of preeclampsia in pregnant women. Both the U.S. Preventive Services Task Force and the American College of Obstetricians and Gynecologists recommend it for high-risk patients, and a major 2026 study out of Parkland Hospital in Dallas found that giving 162 mg of daily aspirin to all pregnant patients at their first prenatal visit resulted in a 29 percent lower rate of severe preeclampsia. For a condition that affects roughly 5 to 8 percent of pregnancies worldwide and has no approved pharmaceutical cure other than delivering the baby, that is a remarkable shift.
But aspirin is only part of the story. An experimental drug called DM199, developed by DiaMedica Therapeutics, is generating serious interest as the first potential pharmacological treatment for preeclampsia itself, not just prevention. Early Phase 2 trial data show significant blood pressure reductions and improved placental blood flow in women already experiencing the condition. This article covers the established science behind aspirin prophylaxis, the new universal aspirin data from 2026, what DM199 could mean for treatment, and the practical questions pregnant women and their families should be asking their doctors. For readers of this site focused on brain health and dementia, the connection matters more than you might think: preeclampsia has been linked in longitudinal research to elevated risk of vascular dementia and cognitive decline later in life.
Table of Contents
- How Does Aspirin Lower the Risk of Preeclampsia During Pregnancy?
- The 2026 Universal Aspirin Study and What It Changes
- DM199 — The Experimental Drug That Could Treat Preeclampsia, Not Just Prevent It
- Who Should Take Aspirin and When Should They Start?
- The Connection Between Preeclampsia and Long-Term Brain Health
- Practical Steps for Families Navigating a High-Risk Pregnancy
- What Comes Next for Preeclampsia Research
- Conclusion
- Frequently Asked Questions
How Does Aspirin Lower the Risk of Preeclampsia During Pregnancy?
Preeclampsia develops when blood vessels that supply the placenta fail to form properly, leading to high blood pressure, protein in the urine, and potentially life-threatening organ damage. Aspirin works by inhibiting the production of thromboxane, a substance that constricts blood vessels and promotes platelet clumping. At low doses, this shifts the balance toward prostacyclin, which dilates blood vessels and improves blood flow to the placenta. The effect is modest but meaningful when measured across large populations. A review of 45 randomized trials involving more than 20,000 pregnant women found significant reductions in preeclampsia, severe preeclampsia, and fetal growth restriction when aspirin was started before 16 weeks of gestation.
The USPSTF found an absolute risk reduction of 2 to 5 percent across approximately 30,000 randomized subjects. That may sound small in percentage terms, but consider what it means at scale: in the United States alone, roughly 3.6 million babies are born each year. Even a conservative estimate suggests that widespread aspirin use among high-risk patients could prevent tens of thousands of cases annually. The current recommendation calls for 81 mg daily, initiated between 12 and 28 weeks of gestation and optimally before 16 weeks, continuing until delivery. The timing matters because the drug needs to influence placental vascular development during a critical window. Starting too late diminishes the benefit substantially.
The 2026 Universal Aspirin Study and What It Changes
The most significant recent development came from research presented at the Society for Maternal-Fetal Medicine’s 2026 Pregnancy Meeting in February. Investigators at Parkland Hospital in Dallas compared outcomes for 18,457 patients who gave birth between 2023 and 2025, after the hospital adopted universal aspirin prescribing in August 2022, against a similar number of patients from before the policy change. Every pregnant patient arriving for a first prenatal visit at or before 16 weeks received 162 mg of daily aspirin, regardless of individual risk factors. The result was a 29 percent lower rate of developing severe preeclampsia compared to those who did not receive aspirin. Two additional findings stood out. First, patients who did develop severe preeclampsia while on aspirin developed it later in pregnancy than those in the control group.
In obstetrics, every additional week of gestation can dramatically improve neonatal outcomes, so delaying onset even modestly is clinically valuable. Second, there was no increase in maternal hemorrhage or placental abruption, which had been a lingering concern about broader aspirin use. Patients with preexisting chronic hypertension who received aspirin were also less likely to develop severe preeclampsia. However, this study has important limitations. It was conducted at a single large urban hospital, and its design was observational rather than a randomized controlled trial. The universal approach also raises questions about whether the benefits justify medicating the roughly 92 to 95 percent of women who would never develop preeclampsia. The study was published as a late-breaking oral abstract in the February 2026 issue of PREGNANCY, SMFM’s peer-reviewed journal, and the broader obstetric community is still debating whether to recommend universal aspirin rather than risk-based prescribing.
DM199 — The Experimental Drug That Could Treat Preeclampsia, Not Just Prevent It
Everything discussed so far involves prevention. Once preeclampsia develops, the only definitive treatment is delivering the baby, which often means premature delivery with all its associated risks. There are currently no approved drug treatments for preeclampsia in the United States or Europe. That is what makes DM199, developed by DiaMedica Therapeutics, so significant. It is the first drug candidate that aims to treat the condition itself. DM199 works by stabilizing the lining of blood vessels and improving placental blood flow while simultaneously lowering maternal blood pressure. This mechanism is important because conventional antihypertensives used during pregnancy, such as labetalol or nifedipine, can reduce blood pressure but may also decrease blood flow to the baby. DM199 appears to avoid that tradeoff. In an ongoing Phase 2 investigator-sponsored trial at Tygerberg Hospital in Cape Town, South Africa, led by researcher Cathy Cluver, over 30 women with late-stage preeclampsia have been dosed.
Interim results reported in July 2025 showed statistically significant reductions in blood pressure and dilation of intrauterine arteries, with no placental transfer of the drug to the fetus. The highest dose group experienced blood pressure reductions of 35 mmHg systolic and 15 mmHg diastolic, which are clinically substantial drops. The FDA has requested one additional non-clinical study, a 10-day modified embryo-fetal development study in a rabbit model, with results expected by the second quarter of 2026. If those results are favorable, the path toward a U.S. clinical trial could open. But caution is warranted. Thirty patients in a Phase 2 trial is a very early signal, not proof of efficacy. Many promising drugs at this stage fail to replicate their results in larger, more rigorous trials. Still, even the possibility of a treatment rather than just prevention represents a fundamental shift in how preeclampsia might be managed.
Who Should Take Aspirin and When Should They Start?
Current guidelines from ACOG identify high-risk factors that qualify a patient for aspirin prophylaxis. These include a history of preeclampsia in a prior pregnancy, chronic hypertension, type 1 or type 2 diabetes, kidney disease, autoimmune conditions such as lupus, and carrying multiples. Moderate risk factors, including first pregnancy, maternal age over 35, obesity, family history of preeclampsia, and certain demographic factors, may also warrant aspirin when two or more are present. The comparison between risk-based and universal prescribing is now a live debate.
Risk-based prescribing targets those most likely to benefit, minimizing unnecessary medication. Universal prescribing, as tested at Parkland Hospital with 162 mg rather than the standard 81 mg, captures patients whose risk factors might be missed or who lack early prenatal care. The tradeoff is straightforward: a universal approach is simpler to implement and eliminates screening gaps, but it means most women taking the drug will derive no benefit from it while accepting a small but nonzero risk of side effects, primarily gastrointestinal discomfort. For patients who begin prenatal care after 16 weeks, the window for meaningful prevention may already be narrowing, and the decision becomes less clear-cut.
The Connection Between Preeclampsia and Long-Term Brain Health
For readers of a brain health and dementia-focused site, preeclampsia is not just an obstetric concern. A growing body of epidemiological evidence links preeclampsia to elevated risk of cardiovascular disease and cerebrovascular disease in the decades following pregnancy. The vascular damage that characterizes preeclampsia, including endothelial dysfunction and chronic inflammation, does not necessarily resolve after delivery. Multiple large cohort studies have found that women with a history of preeclampsia face roughly double the risk of stroke and significantly higher rates of chronic hypertension, both of which are established risk factors for vascular dementia and cognitive decline.
This is worth emphasizing because dementia prevention increasingly focuses on midlife vascular risk management. A woman who develops preeclampsia at age 30 should be monitored more aggressively for hypertension, metabolic syndrome, and other cardiovascular risk factors throughout her 40s and 50s. If aspirin prophylaxis during pregnancy prevents preeclampsia, it may also be interrupting a cascade that contributes to cognitive decline decades later. That connection is still being studied, and no one should overstate the certainty of the link, but it reframes preeclampsia prevention as potentially relevant to long-term neurological health, not just pregnancy outcomes.
Practical Steps for Families Navigating a High-Risk Pregnancy
If you or a family member has been told you are at elevated risk for preeclampsia, the most important step is an early conversation with your obstetric provider about aspirin, ideally at your first prenatal visit and certainly before 16 weeks of gestation. Ask specifically about your risk factors, the recommended dose, and whether your provider follows the USPSTF or ACOG guidelines.
Some providers are already moving toward the 162 mg dose used in the Parkland study rather than the traditional 81 mg, though this is not yet universally adopted. Monitor for warning signs of preeclampsia throughout pregnancy, including persistent headaches, visual changes, upper abdominal pain, sudden swelling, and blood pressure readings above 140/90. Early detection and management, even when prevention fails, dramatically improve outcomes for both mother and baby.
What Comes Next for Preeclampsia Research
The next 12 to 18 months could be pivotal. If DiaMedica’s additional non-clinical study clears the FDA’s requirements by mid-2026, a U.S.-based clinical trial of DM199 could begin, potentially offering the first real pharmacological treatment for active preeclampsia. Meanwhile, the debate over universal versus risk-based aspirin prescribing will likely generate additional large-scale studies.
Researchers are also investigating biomarkers, including the sFlt-1/PlGF ratio, that could allow earlier and more accurate identification of women who will develop preeclampsia, enabling more targeted prevention strategies. For a condition that has been managed essentially the same way for decades, deliver the baby and hope it is not too early, the pace of change is finally accelerating. That matters not only for pregnancy outcomes but, as the vascular connection to dementia becomes clearer, for the long-term cognitive health of millions of women.
Conclusion
Low-dose aspirin remains the frontline drug for reducing preeclampsia risk, with decades of evidence and new 2026 data from nearly 37,000 patients reinforcing its effectiveness. The Parkland Hospital study showing a 29 percent reduction in severe preeclampsia with universal 162 mg aspirin is among the most compelling recent findings in maternal medicine. DM199, while still experimental, represents a genuinely new approach: treating preeclampsia rather than simply trying to prevent it, with early trial data showing meaningful blood pressure reduction and no drug transfer to the fetus. For anyone reading this from a brain health perspective, the takeaway is that preeclampsia is not a condition confined to pregnancy.
Its vascular consequences can echo across decades, contributing to the hypertension and endothelial damage that increase dementia risk later in life. Preventing preeclampsia with something as accessible as aspirin may carry benefits that extend far beyond the delivery room. Talk to your doctor early, know your risk factors, and pay attention to the emerging research. The science is moving, and it is moving in a hopeful direction.
Frequently Asked Questions
Is aspirin safe to take during pregnancy?
Low-dose aspirin (81–162 mg) is considered safe during pregnancy when taken as directed by a healthcare provider. The 2026 Parkland Hospital study involving over 18,000 patients found no increase in maternal hemorrhage or placental abruption. However, aspirin should not be started without medical guidance, particularly in the third trimester or at higher doses.
When should pregnant women start taking aspirin to prevent preeclampsia?
Guidelines recommend starting between 12 and 28 weeks of gestation, with the greatest benefit seen when aspirin is initiated before 16 weeks. The Parkland study began aspirin at the first prenatal visit at or before 16 weeks. Starting after 16 weeks may offer reduced benefit because the critical window for influencing placental vascular development has partially closed.
What is DM199 and is it available now?
DM199 is an experimental drug developed by DiaMedica Therapeutics that has shown early promise in treating active preeclampsia. It is currently in a Phase 2 trial in South Africa with over 30 patients dosed. It is not available to patients outside the trial. The FDA has requested one more non-clinical study before U.S. trials can proceed, with results expected by mid-2026.
Does preeclampsia increase the risk of dementia later in life?
Epidemiological evidence suggests women with a history of preeclampsia face higher rates of cardiovascular disease, stroke, and chronic hypertension in subsequent decades, all of which are established risk factors for vascular dementia. The direct causal link is still being studied, but the vascular damage associated with preeclampsia may contribute to long-term cognitive decline.
What is the difference between preventing preeclampsia and treating it?
Aspirin is a preventive measure taken before preeclampsia develops, reducing the likelihood it will occur. Currently, once preeclampsia develops, the only definitive treatment is delivering the baby. DM199 is significant because it aims to be the first drug that could treat active preeclampsia by lowering blood pressure and improving placental blood flow, potentially allowing pregnancies to continue safely for longer.
Should all pregnant women take aspirin, or only those at high risk?
Current ACOG and USPSTF guidelines recommend aspirin only for women with identified risk factors. The 2026 Parkland study tested a universal approach, giving aspirin to all patients regardless of risk, and found a significant reduction in severe preeclampsia. Whether guidelines will shift to universal prescribing is still being debated by the medical community.
