Preeclampsia

What preeclampsia is

Preeclampsia is a pregnancy-specific condition involving new-onset high blood pressure (after 20 weeks of gestation) combined with signs that one or more organ systems are affected — typically the kidneys (protein in the urine), liver (elevated enzymes), or central nervous system (severe headaches, vision changes).

It affects roughly 5–8% of pregnancies worldwide and is one of the leading causes of maternal and infant illness. The cause isn't fully understood, but it appears to involve abnormal development of the placenta's blood vessels early in pregnancy, which later disrupts blood flow and triggers a cascade of effects throughout the body.

Caught early and managed appropriately, the great majority of preeclampsia cases lead to good outcomes for both parent and baby. The biggest risk factor for poor outcomes is delayed diagnosis.

Symptoms to recognize

Preeclampsia is sneaky — it often develops without symptoms you'd notice at home, which is why blood pressure and urine checks at every prenatal visit matter. When symptoms do appear, the ones to take seriously are:

Warning signs that need a same-day call

Severe, sudden swelling — especially in the face and hands, often noticed when your rings stop fitting or your face looks puffy. Some pregnancy swelling is normal, especially in feet and ankles. Sudden, significant swelling above the waist is different.

Severe headaches that don't respond to acetaminophen, or any headache accompanied by vision changes (blurred vision, seeing spots or flashing lights, brief loss of vision).

Pain in the upper-right belly, just below the ribs — this can indicate liver involvement.

Shortness of breath that's new or sudden — can indicate fluid in the lungs.

Nausea and vomiting that come on suddenly in the second half of pregnancy (different from early morning sickness).

Any one of these symptoms warrants a same-day call to your provider or a trip to labor and delivery. Don't wait to see if it resolves.

Risk factors

Preeclampsia is more common in: first pregnancies, people over 40 or under 18, multiple pregnancies (twins, triplets), people with pre-existing hypertension, kidney disease, diabetes, lupus, or antiphospholipid syndrome, IVF pregnancies, and people with a previous preeclamptic pregnancy or a family history of preeclampsia.

Black women in the US have significantly higher rates of severe preeclampsia and worse outcomes, driven by a combination of medical, genetic, and well-documented healthcare-access disparities. If you're in a higher-risk group, your provider may prescribe low-dose aspirin (81 mg daily) starting in the second trimester — it modestly but meaningfully reduces preeclampsia risk.

How it's diagnosed and monitored

Diagnosis usually starts with two elevated blood-pressure readings (typically ≥140/90, taken 4+ hours apart) after 20 weeks of pregnancy. Confirmation looks for protein in the urine (proteinuria) or signs of organ involvement on blood tests (kidney function, liver enzymes, platelet count).

If preeclampsia is suspected or confirmed, monitoring intensifies: more frequent prenatal visits, blood pressure checks (sometimes at home), regular blood and urine tests, and fetal monitoring (NSTs, growth ultrasounds, biophysical profiles).

Some people are monitored as outpatients; others need hospital admission depending on the severity and how quickly things are changing.

Treatment

There is no treatment for preeclampsia other than delivery — that's the cure. The question becomes when to deliver, balancing the risks to the parent (worsening preeclampsia) against the risks to the baby (prematurity).

Mild preeclampsia at or past 37 weeks is typically managed by delivering. Severe preeclampsia at any gestational age usually means delivery within hours to days. Mild preeclampsia at earlier gestational ages may be monitored carefully to gain more time for the baby to mature, with delivery if anything worsens.

Medications used during management include antihypertensives (to control blood pressure), magnesium sulfate (to prevent seizures, which preeclampsia can progress to — that progression is called eclampsia), and corticosteroids (to mature the baby's lungs before a preterm delivery).

After delivery

Preeclampsia usually resolves within days to weeks after delivery, though blood pressure and lab abnormalities can persist for 6–12 weeks. Close postpartum monitoring is standard, including blood pressure checks for the first few weeks at home.

Some people develop preeclampsia for the first time after delivery (postpartum preeclampsia, usually within 48 hours but occasionally up to 6 weeks). The symptoms are the same as during pregnancy — and just as urgent. The 6-week postpartum window is when many people are out of regular contact with their provider, which is why knowing the warning signs matters.

Having had preeclampsia is associated with higher lifetime cardiovascular risk — including heart disease and stroke — even decades later. Long-term follow-up with primary care for blood pressure, cholesterol, and cardiovascular risk is recommended.

Frequently asked questions

Sources and medical references

• ACOG — Pregnancy complications — Frequently Asked Questions
• Mayo Clinic — Pregnancy week-by-week and complications overview
• NHS — Pregnancy complications
• ACOG — Hypertension in Pregnancy — Practice Bulletin
• Mayo Clinic — Preeclampsia