What Is Preeclampsia in Pregnancy?

Preeclampsia is diagnosed when a pregnant woman has high blood pressure and signs of organ involvement, including protein in the urine (protein proteinuria), elevated liver enzymes, low platelet levels or other changes in the body.

Women can develop preeclampsia even if they never had high blood pressure before. Those with high blood pressure or certain health issues, like kidney disease or diabetes, are at higher risk for preeclampsia.

Regular prenatal checkups help detect preeclampsia early, allowing for timely treatment to protect both mother and baby. 

“If you have risk factors, talk to your doctor about changes you can make before and during your pregnancy to lower your chances of developing preeclampsia,” says Elizabeth Silverman, MD, an OB-GYN at Scripps Clinic La Jolla. “These may include losing weight, quitting smoking and controlling high blood pressure. In some cases, taking a low dose of aspirin (81 mg daily) may be recommended starting in the second trimester.”

At Scripps, OB-GYN and maternal fetal medicine specialists provide high-level expert care for pregnant women with high blood pressure conditions like preeclampsia and gestational diabetes.

If not treated, preeclampsia can lead to serious complications for the mother, including:

• Kidney or liver damage
• Blood clotting problems
• Severe headaches or vision loss
• Seizures (eclampsia)
• Stroke
• HELLP syndrome, a severe form of preeclampsia

Preeclampsia can also affect the baby by reducing blood flow through the placenta, increasing the risk of:

• Premature birth
• Low birth weight
• Restricted fetal growth

Doctors now classify preeclampsia into two categories:

Preeclampsia without severe features

This type is characterized by:

• Blood pressure of 140 mmHg or higher (top number) or 90 mmHg or higher (bottom number)
• Protein in urine or mild laboratory abnormalities

Even without severe symptoms, preeclampsia requires close monitoring.

Women with preeclampsia without severe features typically have frequent blood pressure checks, lab tests and fetal ultrasounds to watch for signs that the condition is worsening. If the pregnancy has reached 37 weeks or later, doctors may recommend delivery to lower the risk of complications for both mother and baby.

Preeclampsia with severe features

Preeclampsia with severe features is more serious and can increase the risk of complications for both mother and baby. It is treated as an urgent, high-risk condition because it can progress quickly.

“Pregnancies complicated by preeclampsia with severe features are particularly concerning because the ability of the placenta to provide adequate nutrition and oxygen to the fetus can be impaired,” says Dr. Silverman.

When the placenta is affected, the baby may not receive enough oxygen or nutrients to grow properly. This increases the risk of serious complications and often affects how quickly doctors recommend delivery.

Some women with preeclampsia may have symptoms such as:

• Swelling in the hands or face
• Sudden weight gain over one to two days
• Headaches
• Upper abdominal pain
• Shortness of breath
• Vision changes (blurry vision, flashing lights)
• Nausea or vomiting

Get medical help right away if you have any of the following symptoms, which may be signs of preeclampsia with severe features:

• Severe-range blood pressure: 160 mmHg or higher (top number) or 110 mmHg or higher (bottom number)
• Severe headaches that don’t improve with medication
• Severe upper abdominal pain (often on the right side)
• Abnormal blood tests, including high liver enzymes or low platelet counts
• Chest pain or shortness of breath

Preeclampsia affects about 5 to 10% of pregnancies and most often develops in the third trimester though it can occur at any time after 20 weeks of pregnancy or even after delivery.

Doctors classify the risk of developing preeclampsia as high or moderate.

High risk factors

• Preeclampsia in a previous pregnancy
• Being pregnant with multiple babies
• Chronic high blood pressure
• Kidney disease
• Diabetes
• Autoimmune conditions such as lupus

Moderate risk factors

• First pregnancy
• Pregnancy more than 10 years after a prior birth
• Obesity
• Family history of preeclampsia
• Maternal age 35 or older
• Pregnancy achieved through in vitro fertilization

Black women have higher rates of preeclampsia and pregnancy-related complications. This is largely due to differences in access to quality health care and everyday factors that can affect health, like stress, housing and access to healthy food. Growing awareness has led to increased efforts to address these issues.

Doctors diagnose preeclampsia through a combination of tests, including:

• Blood pressure measurements
• Urine tests to check for protein
• Blood tests to assess liver function and platelet levels

Ultrasound exams are used to monitor fetal growth and amniotic fluid levels, helping providers determine the severity of the condition and guide treatment decisions.

Treatment for preeclampsia depends on how severe the condition is and how far along the pregnancy has progressed.

Women with preeclampsia without severe features who are less than 37 weeks pregnant may be cared for with close monitoring, including:

• Increased rest and activity adjustments
• Frequent blood pressure monitoring
• Regular ultrasounds to track fetal growth
• Monitoring fetal heart rate and amniotic fluid

Preeclampsia often improves after birth, but some women may still need medication or hospital care to control blood pressure before or after delivery, especially if symptoms are severe.

Because preeclampsia is caused by pregnancy-related changes, delivery is the only way to fully resolve the condition. The timing of delivery is carefully weighed against the risks of continuing the pregnancy.

“The only real cure for preeclampsia is to give birth,” says Dr. Silverman. “If the pregnancy is far enough along or if signs and symptoms of preeclampsia with severe features develop, then your doctor may recommend induction of labor or delivery by cesarean section in certain cases.”

Symptoms can persist for several weeks postpartum and may require continued treatment and follow-up care.

There is no certain way to prevent preeclampsia, but steps can be taken to lower your risk.

• Attend all prenatal visits
• Follow your doctor’s recommendations for diet, activity and rest
• Manage chronic conditions, such as high blood pressure or diabetes
• Use low-dose aspirin if recommended by your doctor

Get medical help right away if you develop symptoms, such as severe headaches, chest pain, shortness of breath or severe upper abdominal pain. These can be signs of preeclampsia with severe features and should not be ignored.