Preeclampsia is a serious blood pressure disorder that develops during pregnancy, typically after 20 weeks. It’s diagnosed when blood pressure reaches 140/90 mmHg or higher along with signs of organ stress, most commonly protein in the urine or problems with the liver or kidneys. Preeclampsia affects roughly 5 to 8 percent of pregnancies and is one of the leading causes of maternal and fetal complications worldwide.
What Happens in Your Body
Preeclampsia starts with the placenta. In a healthy pregnancy, the placenta establishes a robust blood supply by remodeling the arteries in the uterine wall, widening them to deliver oxygen and nutrients to the growing baby. In preeclampsia, this remodeling process goes wrong. The cells that are supposed to anchor the placenta into the uterine wall don’t invade deeply enough, and the outer layer of the placenta undergoes premature aging and stress at the cellular level.
This dysfunctional placenta then leaks harmful proteins into the mother’s bloodstream. These proteins block the formation of new blood vessels and trigger inflammation that damages the lining of blood vessels throughout the body. That widespread damage to blood vessel walls is what drives the hallmark features of preeclampsia: high blood pressure, protein spilling into the urine, swelling, and potentially organ damage in the liver, kidneys, and brain.
Who Is Most at Risk
Certain factors make preeclampsia significantly more likely. A personal history of preeclampsia in a previous pregnancy is one of the strongest predictors. Other high-risk factors include chronic high blood pressure, kidney disease, autoimmune conditions like lupus, and type 1 or type 2 diabetes. Carrying multiples (twins or more) also raises risk substantially.
First pregnancies carry higher risk than subsequent ones, as do pregnancies in women over 35 or under 20. Obesity, a family history of preeclampsia, and pregnancies conceived through IVF are additional risk factors. Having one of these factors doesn’t mean you’ll develop preeclampsia, but it does mean closer monitoring is warranted.
Symptoms and Warning Signs
Preeclampsia can be deceptive. Many women feel fine in the early stages, and the condition is often caught first through routine blood pressure checks at prenatal visits. That’s one reason those appointments matter so much in the second half of pregnancy.
When symptoms do appear, they can include persistent headaches that don’t respond to typical remedies, visual changes like blurriness, light sensitivity, or dark spots that won’t go away, and pain in the upper right side of the abdomen (where the liver sits). Sudden swelling in the face and hands, as opposed to the gradual ankle swelling common in normal pregnancy, can also be a sign. Shortness of breath and sudden weight gain over a few days may point to fluid retention driven by preeclampsia.
Certain symptoms signal an emergency: sharp abdominal pain on the right side, seizure-like twitching or convulsing, severe headache, blurred vision, or difficulty breathing. These warrant an immediate trip to the hospital, not a phone call to schedule an appointment.
How It’s Diagnosed
Diagnosis centers on blood pressure readings and evidence that organs are under strain. Blood pressure of 140/90 mmHg or higher on two separate readings, combined with protein in the urine or abnormal blood work showing liver or kidney problems, confirms the diagnosis. Severe preeclampsia is defined by blood pressure reaching 160/110 mmHg or higher, or by signs of significant organ damage regardless of blood pressure level.
Your provider will typically check blood pressure at every prenatal visit and test your urine for protein. If preeclampsia is suspected, additional blood tests evaluate liver function, kidney function, and platelet counts (the blood cells involved in clotting).
HELLP Syndrome: A Dangerous Complication
HELLP syndrome is a severe form of preeclampsia that affects the blood and liver. The name stands for hemolysis (red blood cells breaking apart), elevated liver enzymes, and low platelets. It can develop rapidly, sometimes before preeclampsia itself is recognized.
HELLP is diagnosed when platelet counts drop below 100,000 per microliter (normal is 150,000 to 400,000), liver enzymes rise above 70 IU/L, and blood tests show red blood cells are being destroyed. It can cause liver rupture, stroke, and organ failure if not treated quickly. Delivery is usually necessary regardless of how far along the pregnancy is.
Treatment and Delivery
The only cure for preeclampsia is delivering the baby and the placenta. The timing of delivery depends on how severe the condition is and how far along you are. With mild preeclampsia, your provider may monitor you closely and aim to reach at least 37 weeks. With severe features, delivery often needs to happen sooner, even if the baby is premature, to protect the mother’s life.
Before delivery, treatment focuses on preventing complications. If the condition is severe, magnesium sulfate is given intravenously to prevent seizures (a condition called eclampsia). It’s typically administered for less than 48 hours and is the standard of care recommended by both ACOG and the Society for Maternal-Fetal Medicine. Blood pressure medications are used to bring dangerously high readings under control. If the baby needs to be delivered early, corticosteroid injections help mature the baby’s lungs.
Preeclampsia After Delivery
Most people assume the risk disappears once the baby is born, but preeclampsia can develop or worsen after delivery. Most postpartum cases appear within 48 hours of childbirth, though symptoms can emerge up to six weeks later. The warning signs are the same: severe headaches, visual changes, upper abdominal pain, and high blood pressure readings.
Clinicians generally treat severe blood pressure elevations as a medical emergency for up to six weeks postpartum because of the ongoing risk. If you had preeclampsia during pregnancy, expect blood pressure monitoring to continue in the weeks following delivery.
Prevention With Low-Dose Aspirin
For women at high risk, low-dose aspirin (81 mg per day) can reduce the chance of developing preeclampsia. The American College of Obstetricians and Gynecologists recommends starting it between 12 and 28 weeks of gestation, ideally before 16 weeks, and continuing daily until delivery. This applies to women with a history of preeclampsia, chronic hypertension, kidney disease, autoimmune conditions, or multiple high-risk factors. It’s a simple, inexpensive intervention with good evidence behind it.
Long-Term Heart Health
Preeclampsia isn’t just a pregnancy complication. It’s now recognized as an independent risk factor for cardiovascular disease later in life. A large meta-analysis published in the American Heart Association’s journals found that women who had preeclampsia face roughly four times the risk of developing heart failure compared to women with uncomplicated pregnancies. The risk of coronary heart disease doubles, stroke risk increases by about 80 percent, and the risk of dying from cardiovascular disease is more than twice as high.
These elevated risks persist even after accounting for other factors like obesity and smoking. If you’ve had preeclampsia, it’s worth treating that history as a signal to stay on top of blood pressure, cholesterol, and other cardiovascular markers in the years and decades that follow. Many cardiologists now consider a history of preeclampsia a meaningful part of a woman’s heart disease risk profile.