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Preeclampsia is a serious pregnancy complication characterized by high blood pressure and signs of organ damage, most commonly affecting the kidneys and liver. It typically develops after 20 weeks of gestation and affects approximately 5 to 8 percent of pregnancies worldwide. While mild cases can be managed with close monitoring, severe preeclampsia can be life-threatening for both the mother and the baby. Understanding the risk factors, recognizing the warning signs, and knowing when to seek emergency care are essential for every pregnant person and their support network.
Preeclampsia is a multisystem disorder unique to pregnancy. It is defined by new-onset hypertension (blood pressure of 140/90 mmHg or higher on two separate measurements) after 20 weeks of gestation, along with evidence of end-organ damage. The most common signs of organ involvement include protein in the urine (proteinuria), elevated liver enzymes, low platelet count, kidney dysfunction, and neurological symptoms.
The exact cause of preeclampsia is not fully understood, but research suggests it originates in the placenta. In a normal pregnancy, blood vessels that supply the placenta remodel to allow increased blood flow. In preeclampsia, this remodeling is incomplete, leading to reduced placental blood flow, oxidative stress, and the release of substances into the mother's bloodstream that damage blood vessel walls throughout the body. This widespread vascular dysfunction is what produces the hallmark symptoms of the disease.
Preeclampsia can range from mild to severe, and it can progress rapidly. In some cases, it develops for the first time during labor or even in the postpartum period, up to six weeks after delivery.
While preeclampsia can occur in any pregnancy, certain factors increase the risk. Having had preeclampsia in a previous pregnancy is the strongest risk factor, with a recurrence rate of approximately 15 to 20 percent. Other high-risk factors include chronic hypertension, pregestational diabetes (type 1 or type 2), kidney disease, autoimmune conditions such as lupus or antiphospholipid syndrome, and a history of multifetal pregnancy (twins, triplets).
Moderate risk factors include a first pregnancy (nulliparity), advanced maternal age (35 or older), obesity with a body mass index of 30 or higher, a family history of preeclampsia in a mother or sister, a pregnancy conceived through in vitro fertilization (IVF), and an interpregnancy interval of more than 10 years.
According to ACOG, individuals with one high-risk factor or two or more moderate risk factors should be offered low-dose aspirin (81 mg daily) for preeclampsia prevention, starting between 12 and 16 weeks of gestation and continuing until delivery. Evidence shows that this intervention reduces the risk of preeclampsia by approximately 15 to 20 percent in high-risk populations.
Recognizing the symptoms of preeclampsia can be lifesaving. Many cases are initially detected through routine blood pressure monitoring at prenatal visits, which is one of the reasons consistent prenatal care is so important. However, symptoms can develop suddenly between visits.
The key warning signs include a severe or persistent headache that does not respond to over-the-counter medication, visual changes such as blurred vision, seeing spots or flashing lights, or temporary loss of vision, and upper abdominal pain, particularly under the right rib cage, which may indicate liver involvement. Other important symptoms include sudden swelling of the face, hands, or feet (while some swelling is normal in pregnancy, rapid or severe swelling is not), nausea or vomiting that develops in the second half of pregnancy, shortness of breath that may indicate fluid in the lungs, and a significant decrease in urine output.
If you experience any of these symptoms, contact your healthcare provider immediately or go to your nearest labor and delivery unit. Do not wait for your next scheduled appointment. Preeclampsia can progress from mild to severe within hours to days.
Preeclampsia is diagnosed based on blood pressure readings and laboratory findings. A blood pressure of 140/90 mmHg or higher, measured on two occasions at least four hours apart, combined with new proteinuria (300 mg or more of protein in a 24-hour urine collection or a protein-to-creatinine ratio of 0.3 or higher) establishes the diagnosis. Preeclampsia can also be diagnosed in the absence of proteinuria if there is evidence of other end-organ dysfunction.
Preeclampsia is classified as having severe features when blood pressure reaches 160/110 mmHg or higher, when there is a platelet count below 100,000, when liver enzymes are elevated to twice the normal upper limit, when serum creatinine rises above 1.1 mg/dL (indicating kidney impairment), when pulmonary edema develops, or when there are new-onset cerebral or visual symptoms.
HELLP syndrome is a particularly dangerous variant of severe preeclampsia. The acronym stands for Hemolysis, Elevated Liver enzymes, and Low Platelet count. HELLP syndrome can develop rapidly and may occur even before blood pressure becomes significantly elevated. It requires immediate medical management and typically urgent delivery.
Delivery of the baby and the placenta is the only definitive treatment for preeclampsia, as the condition resolves once the placenta is removed. The critical clinical decision is the timing of delivery, which depends on the severity of the disease and the gestational age of the baby.
For preeclampsia without severe features diagnosed at or after 37 weeks, delivery is generally recommended promptly. For cases diagnosed between 34 and 37 weeks without severe features, management may involve close monitoring with the goal of reaching at least 37 weeks if the condition remains stable. For preeclampsia with severe features at 34 weeks or later, delivery is typically recommended after stabilization. Before 34 weeks, the decision involves weighing the risks of prematurity against the risks of continuing the pregnancy, and corticosteroids are administered to accelerate fetal lung development.
Magnesium sulfate is the standard medication used to prevent seizures (eclampsia) in women with preeclampsia with severe features. It is typically administered intravenously during labor and for 24 to 48 hours after delivery. Antihypertensive medications such as labetalol, hydralazine, or nifedipine are used to manage severely elevated blood pressure and reduce the risk of stroke.
Expectant management, meaning close monitoring without immediate delivery, may be considered for preeclampsia with severe features before 34 weeks in carefully selected cases at facilities with maternal-fetal medicine expertise and neonatal intensive care capabilities.
One of the most important but often overlooked aspects of preeclampsia is its impact on long-term health. Research consistently shows that individuals who have had preeclampsia face a significantly elevated risk of cardiovascular disease later in life. Studies indicate a 3 to 4 times higher risk of chronic hypertension, a 2 times higher risk of coronary heart disease and stroke, and an increased risk of heart failure and type 2 diabetes.
The American Heart Association (AHA) now recognizes a history of preeclampsia as a risk factor for cardiovascular disease. This means that if you have had preeclampsia, you should inform all of your healthcare providers, not just your OB/GYN, so that appropriate screening and preventive measures can be implemented.
Recommendations for long-term cardiovascular health after preeclampsia include annual blood pressure monitoring, regular screening for diabetes and lipid disorders, maintaining a healthy weight, engaging in regular physical activity, following a heart-healthy diet, and avoiding smoking. Your primary care provider should be aware of your pregnancy history and may recommend earlier or more frequent cardiovascular screening than standard guidelines suggest.
While preeclampsia cannot always be prevented, evidence-based strategies can reduce the risk. As mentioned, low-dose aspirin (81 mg daily) is recommended for high-risk individuals starting between 12 and 16 weeks of gestation. This is one of the most effective and well-studied preventive interventions available.
Other preventive strategies supported by evidence include adequate calcium supplementation (1,000 to 2,000 mg daily, particularly in populations with low dietary calcium intake), regular physical activity during pregnancy as advised by your provider, managing pre-existing conditions such as hypertension and diabetes before and during pregnancy, and attending all scheduled prenatal visits for blood pressure and urine monitoring.
Research into additional prevention strategies is ongoing. Some studies are investigating the role of specific biomarkers in early pregnancy to better predict who will develop preeclampsia, which could allow for more targeted prevention in the future.
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