Preeclampsia complicates approximately 5 to 8% of all pregnancies in the United States, making it one of the leading causes of maternal and fetal morbidity worldwide. The symptoms of preeclampsia can appear suddenly, sometimes escalating from mild to life-threatening within hours or days. High blood pressure and protein in the urine are the clinical hallmarks, but many women experience a constellation of warning signs, including persistent headaches, visual disturbances, and upper abdominal pain, that signal the condition before lab tests confirm it. Recognizing these symptoms quickly can be the difference between a managed delivery and a maternal emergency.
According to the Preeclampsia Foundation, preeclampsia and related hypertensive disorders account for approximately 15% of premature births and are responsible for 70,000 maternal deaths globally each year. If you are pregnant or planning to become pregnant, understanding these warning signs is essential. Our medical conditions guide covers this and other health conditions in detail.
What Is Preeclampsia?
Preeclampsia is a pregnancy-specific disorder characterized by new-onset high blood pressure (140/90 mmHg or higher) and typically proteinuria (protein in the urine) developing after 20 weeks of gestation. According to the American College of Obstetricians and Gynecologists, the diagnostic criteria were updated in 2013 to recognize that preeclampsia can occur without proteinuria if other signs of organ damage are present, including elevated liver enzymes, low platelet count, kidney dysfunction, or neurological symptoms.
The exact cause of preeclampsia is not fully understood, but research suggests it originates from abnormal placental development early in pregnancy. The poorly formed placental blood vessels lead to reduced blood flow, which triggers the release of substances that damage the mother’s blood vessel lining throughout the body. This systemic vascular damage is what produces the wide-ranging symptoms affecting multiple organs.
Preeclampsia is progressive. Without intervention, it can advance to eclampsia (seizures), HELLP syndrome (hemolysis, elevated liver enzymes, low platelets), placental abruption, stroke, organ failure, and death. The only definitive cure is delivery of the baby and placenta, though timing delivery is a delicate balance between maternal safety and fetal maturity.
The Primary Symptoms of Preeclampsia
High Blood Pressure
Elevated blood pressure is the most reliable indicator of preeclampsia. A reading of 140/90 mmHg or higher on two separate occasions at least 4 hours apart, after 20 weeks of pregnancy in a woman with previously normal blood pressure, meets the diagnostic threshold. Blood pressure of 160/110 mmHg or higher is considered severe and requires immediate treatment.
Many women with preeclampsia do not “feel” their elevated blood pressure, which is why regular prenatal visits with blood pressure checks are so important. According to the National Heart, Lung, and Blood Institute, home blood pressure monitoring during pregnancy can help detect rising numbers between appointments. If you are at risk, your provider may recommend a home cuff.
Protein in Urine (Proteinuria)
Proteinuria indicates that the kidneys are being damaged by the disease process. It is detected through a urine dipstick test at prenatal visits or a 24-hour urine collection. A level of 300 mg or more in a 24-hour collection, or a protein-to-creatinine ratio of 0.3 or higher, meets the diagnostic threshold. Some women notice foamy or bubbly urine, which can indicate high protein levels, though this sign is not always present or reliable.
Severe Headaches
A persistent, severe headache that does not respond to acetaminophen is one of the most important symptoms of preeclampsia to recognize. Unlike typical pregnancy headaches (often caused by hormones, dehydration, or tension), preeclampsia headaches tend to be intense, throbbing, and centered in the front or temples. They may be accompanied by a sense of pressure. The Mayo Clinic lists severe headache as a warning sign that warrants immediate medical evaluation.
Visual Disturbances
Vision changes in preeclampsia include blurred vision, seeing spots or flashing lights, temporary loss of vision, and light sensitivity. These symptoms indicate that the blood vessels in the retina or visual cortex of the brain are being affected. Any new visual disturbance during pregnancy should be reported to your healthcare provider immediately, as it can precede eclamptic seizures.
Additional Warning Signs
Upper abdominal pain: Pain in the upper right abdomen, below the ribs, can indicate liver involvement and is one of the more ominous signs of preeclampsia or HELLP syndrome. The pain may feel like heartburn or gallbladder pain but does not improve with antacids. This symptom reflects liver swelling or capsule stretching and requires urgent evaluation.
Sudden weight gain and swelling: While some swelling is normal during pregnancy, sudden or severe swelling in the face, hands, and feet, especially if it develops rapidly over a few days, can indicate preeclampsia-related fluid retention. Weight gain of more than 3 to 5 pounds in a single week during the third trimester should be reported. However, the CDC notes that swelling alone is not diagnostic, as it occurs in many normal pregnancies.
Decreased urine output: Producing significantly less urine than usual indicates that the kidneys are being affected by the disease. Track your fluid intake and output if you suspect preeclampsia.
Nausea or vomiting: Nausea that develops or returns in the second half of pregnancy, particularly if accompanied by upper abdominal pain, can indicate preeclampsia or HELLP syndrome. This is distinct from first-trimester morning sickness.
Shortness of breath: Fluid accumulation in the lungs (pulmonary edema) is a serious complication of severe preeclampsia. New-onset breathlessness, especially when lying down, should be evaluated urgently.
Risk Factors for Preeclampsia
Certain women face a higher risk of developing preeclampsia. According to the National Institutes of Health, the most significant risk factors include:
First pregnancy: Preeclampsia is more common in first-time mothers, affecting approximately 3 to 5% of first pregnancies compared to 1 to 2% of subsequent ones.
History of preeclampsia: Women who had preeclampsia in a previous pregnancy have a 15 to 20% risk of developing it again.
Chronic hypertension: Pre-existing high blood pressure significantly increases risk. Superimposed preeclampsia (preeclampsia developing on top of chronic hypertension) tends to be more severe and develop earlier in pregnancy.
Other risk factors: Obesity (BMI over 30), maternal age over 35 or under 20, multiple gestation (twins, triplets), diabetes, kidney disease, autoimmune conditions (lupus, antiphospholipid syndrome), and African American race are all associated with elevated risk. The U.S. Preventive Services Task Force recommends low-dose aspirin (81 mg daily) starting at 12 weeks for women with one or more high-risk factors.
Preeclampsia vs. Normal Pregnancy Symptoms
Distinguishing preeclampsia symptoms from normal pregnancy discomforts is a common challenge. This section clarifies the key differences.
Normal pregnancy swelling develops gradually, is usually worse in the feet and ankles at the end of the day, and improves with elevation and rest. Preeclampsia swelling can be sudden, involves the face and hands, does not improve with rest, and may be accompanied by rapid weight gain.
Normal pregnancy headaches respond to rest, hydration, and acetaminophen. Preeclampsia headaches are persistent, severe, and do not respond to standard treatments.
Normal pregnancy fatigue is persistent but stable. Preeclampsia fatigue may be accompanied by visual changes, upper abdominal pain, or other warning signs.
When in doubt, contact your healthcare provider. No experienced obstetrician will dismiss a pregnant woman’s concern about preeclampsia symptoms.
Postpartum Preeclampsia
An important and often overlooked fact is that preeclampsia can develop after delivery, typically within 48 hours but sometimes up to 6 weeks postpartum. According to the American College of Obstetricians and Gynecologists, postpartum preeclampsia accounts for a significant proportion of maternal morbidity and mortality because women and providers may not expect it after delivery.
Symptoms are the same as antepartum preeclampsia: severe headache, visual changes, upper abdominal pain, severe swelling, and high blood pressure. If you experience any of these symptoms in the weeks following delivery, seek immediate medical attention even if you had a normal pregnancy and delivery.
When to seek emergency care: Call 911 or go to the nearest emergency room if you experience blood pressure above 160/110, severe headache that does not respond to acetaminophen, visual changes (blurred vision, seeing spots, temporary vision loss), upper right abdominal pain with nausea, seizures (eclampsia), sudden severe swelling in the face or difficulty breathing, or significantly decreased fetal movement.
Frequently Asked Questions
Can preeclampsia be prevented?
Preeclampsia cannot be fully prevented, but risk can be reduced. Low-dose aspirin (81 mg daily) starting at 12 to 16 weeks of gestation has been shown to reduce preeclampsia risk by 15 to 25% in high-risk women. Adequate calcium intake (1,000 to 1,500 mg daily), regular prenatal care, maintaining a healthy weight before pregnancy, and managing pre-existing conditions like hypertension and diabetes also help reduce risk.
At what week does preeclampsia usually develop?
Preeclampsia typically develops after 20 weeks of gestation, most commonly in the third trimester (after 34 weeks). However, it can occur as early as 20 weeks and as late as 6 weeks postpartum. Early-onset preeclampsia (before 34 weeks) tends to be more severe and carries greater risks for both mother and baby.
Does preeclampsia always require early delivery?
Not always. Mild preeclampsia diagnosed at or near term (37 weeks or later) typically leads to delivery within a few days, which is the definitive treatment. Preeclampsia diagnosed before 34 weeks presents a management dilemma: doctors try to prolong pregnancy to give the baby more time to develop while closely monitoring the mother for worsening symptoms. Severe preeclampsia or HELLP syndrome at any gestational age usually requires delivery within 24 to 48 hours after administering corticosteroids for fetal lung maturity.
Will I get preeclampsia again in my next pregnancy?
If you had preeclampsia in a previous pregnancy, your recurrence risk is approximately 15 to 20% in subsequent pregnancies. The risk is higher if preeclampsia was severe or early-onset. Discuss preventive measures like low-dose aspirin with your obstetrician early in your next pregnancy. Close monitoring with more frequent prenatal visits and early blood pressure screening is typically recommended.
Does preeclampsia affect long-term health?
Yes. Women who have had preeclampsia face a 2 to 4 times higher risk of developing cardiovascular disease, hypertension, and stroke later in life, according to the American Heart Association. Annual cardiovascular screening including blood pressure, cholesterol, and blood sugar monitoring is recommended for all women with a history of preeclampsia.
What to Do Next
If you are pregnant, the most important action is attending all prenatal appointments, where blood pressure and urine protein are routinely checked. Between appointments, be alert for the symptoms of preeclampsia described above, and do not hesitate to call your provider if something feels wrong. Many obstetricians prefer to evaluate a “false alarm” rather than miss a developing case of preeclampsia.
If you have risk factors, discuss low-dose aspirin prophylaxis with your provider at your first prenatal visit. Consider purchasing a home blood pressure cuff (validated for pregnancy use) to monitor between appointments, especially in the third trimester. Keep a symptom diary noting headaches, swelling changes, visual symptoms, and daily weight, so you can quickly identify concerning patterns.
Preeclampsia is unpredictable but not undetectable. Awareness of its symptoms, combined with regular prenatal care, gives you the best chance of catching it early and ensuring the safest possible outcome for you and your baby. For related reading on women’s health conditions, see our articles on symptoms of ovarian cancer and symptoms of heart failure.