Yes, you can have preeclampsia without high blood pressure, and it happens more often than most people realize. This presentation is sometimes called “atypical preeclampsia,” and it can include organ damage, dangerously low platelet counts, liver problems, or even seizures while blood pressure readings remain normal. Because high blood pressure is considered the hallmark of preeclampsia, these cases are frequently missed or diagnosed late.
What Atypical Preeclampsia Looks Like
Classic preeclampsia is defined by blood pressure at or above 140/90 mmHg combined with protein in the urine. But the disease is fundamentally about damage to blood vessels and organs, not just elevated blood pressure. When that damage occurs without a significant rise in blood pressure, or before blood pressure climbs, it falls into the atypical category.
There is no single strict definition, but atypical preeclampsia generally includes cases where a pregnant person has protein in the urine with normal or only marginally elevated blood pressure, or has signs of organ damage (liver dysfunction, kidney impairment, low platelets) without meeting the standard blood pressure threshold. HELLP syndrome, a severe complication involving the breakdown of red blood cells, elevated liver enzymes, and low platelet counts, occurs without hypertension in roughly 20% of cases. Some of these patients also have little or no protein in the urine, making the diagnosis even harder to catch on routine screening.
Why Blood Pressure Can Stay Normal
The root cause of preeclampsia is abnormal placental development. Early in pregnancy, the placenta is supposed to remodel the blood vessels in the uterine wall so they can deliver large volumes of blood to the growing fetus. When this process fails, the placenta becomes oxygen-starved and begins releasing inflammatory substances, free radicals, and proteins that damage the lining of blood vessels throughout the body.
That widespread blood vessel damage is what typically drives blood pressure up. Damaged vessel walls become more reactive to signals that constrict them, and the body compensates for reduced blood flow to the placenta by raising systemic pressure. But the same process also damages organs directly. Liver cells can be injured, platelets consumed, kidneys impaired, and the brain affected, all through the same mechanism of endothelial dysfunction. In some women, this organ-level damage outpaces the rise in blood pressure, meaning serious complications arrive before a blood pressure cuff ever flags a problem.
Seizures Can Happen at Normal Blood Pressure
One of the most striking findings in the research is how often eclamptic seizures occur without preceding high blood pressure. Studies have found that approximately 40% of women who develop eclampsia have seizures at normal blood pressure and without proteinuria. In one UK study, high diastolic blood pressure (120 mmHg or above) was recorded in only 20% of eclampsia patients. Another study of 53 eclampsia cases found that just 13% of the women would have been classified as having severe preeclampsia before the seizure happened.
These numbers suggest that eclampsia is not simply the end stage of worsening high blood pressure. The brain can be affected by the same inflammatory cascade and blood vessel injury that characterizes preeclampsia, even when blood pressure remains in a range that looks reassuring on paper.
Symptoms to Watch For
Because blood pressure may not serve as a warning signal, the physical symptoms of preeclampsia become especially important. These include:
- Severe headaches that don’t respond to typical pain relief
- Vision changes such as blurred vision, light sensitivity, or temporary loss of vision
- Upper right abdominal pain, often felt just below the ribs, which can indicate liver involvement
- Nausea or vomiting that develops in the second half of pregnancy after earlier nausea had resolved
- Shortness of breath caused by fluid accumulating in the lungs
- Sudden swelling of the face and hands, or rapid weight gain over a few days
Any of these symptoms in the second half of pregnancy deserves urgent evaluation, even if your blood pressure has been normal at every appointment. Preeclampsia can develop suddenly, and organ damage sometimes appears before hypertension is ever detected.
How It Gets Diagnosed Without High Blood Pressure
When blood pressure is normal but symptoms or lab results suggest something is wrong, providers look at markers of organ function. A platelet count below 150,000 per microliter is the most common blood-clotting abnormality in preeclampsia, affecting about 20% of patients. Liver enzymes (AST and ALT) elevated to twice the normal upper limit point to liver involvement. A creatinine level above 1.1 mg/dL signals that the kidneys are struggling. Protein in the urine, while not always present, adds to the picture.
No single test confirms atypical preeclampsia. The diagnosis comes from recognizing a pattern: the combination of symptoms, lab abnormalities, and the timing of pregnancy. This is one reason atypical cases are sometimes missed initially, particularly when a provider sees reassuring blood pressure numbers and doesn’t investigate further.
Postpartum Preeclampsia Without Warning
Preeclampsia doesn’t always resolve the moment the baby is delivered. Most postpartum cases develop within 48 hours of birth, but late postpartum preeclampsia and eclampsia can occur up to four weeks after delivery. In documented cases, women who had completely normal blood pressure during labor and delivery developed seizures or organ damage hours to days later.
In one published case, a woman developed a generalized seizure four hours after delivery while still normotensive. A urine test the following day revealed protein that hadn’t been present before. The first sign of her preeclampsia was neurological, not cardiovascular. Cases like this illustrate why postpartum symptoms like severe headaches, visual disturbances, or upper abdominal pain should be taken seriously regardless of what blood pressure readings show.
Why This Matters for Prenatal Care
Standard prenatal screening relies heavily on blood pressure checks and urine dips for protein. These catch classic preeclampsia well, but they can miss atypical presentations entirely. If you have risk factors for preeclampsia (first pregnancy, obesity, a history of preeclampsia, carrying multiples, chronic kidney disease, or autoimmune conditions), paying attention to how you feel becomes an important layer of monitoring beyond what routine vitals can capture.
The key takeaway is straightforward: preeclampsia is a disease of blood vessels and organs, and high blood pressure is just one of its possible expressions. Normal blood pressure during pregnancy does not guarantee that preeclampsia isn’t developing. Symptoms like persistent headaches, vision changes, or right-sided abdominal pain warrant lab work and a closer look, even when the numbers on the blood pressure cuff look fine.