Third-Trimester Preeclampsia: Recognize Warning Signs

Preeclampsia in the Third Trimester: Why Early Recognition Matters

That final stretch of pregnancy is exciting—and full of body changes. Some are normal, but others signal a serious condition called preeclampsia. Knowing the preeclampsia warning signs can help you and your care team act quickly to protect you and your baby.

Preeclampsia is a pregnancy complication that usually starts after 20 weeks. It’s defined by high blood pressure plus signs that organs (often the liver or kidneys) are under strain. It affects about 5–8% of pregnancies, and most cases appear in the third trimester (after 27 weeks) (American College of Obstetricians and Gynecologists [ACOG]; Mayo Clinic). Left untreated, preeclampsia can lead to complications such as preterm birth, organ damage, fluid in the lungs, seizures (eclampsia), stroke, and—in rare cases—death for parent or baby (Johns Hopkins Medicine).

Key takeaway: Early recognition and prompt care save lives. If something feels off, trust your instincts and call your provider.

Preeclampsia 101: What It Is and How It Differs from Other Hypertension

Preeclampsia combines high blood pressure in pregnancy with signs of organ involvement. It typically arises after 20 weeks in someone whose blood pressure was previously normal. It may also appear postpartum.

How it differs from other pregnancy-related hypertension (Mayo Clinic):

Gestational hypertension: High blood pressure after 20 weeks without protein in the urine or other organ problems. Some cases progress to preeclampsia.
Chronic hypertension: High blood pressure present before pregnancy, before 20 weeks, or continuing more than 3 months after birth.
Chronic hypertension with superimposed preeclampsia: Pre-existing high blood pressure that worsens with new proteinuria or organ changes during pregnancy.

Related complications:

Eclampsia: Preeclampsia plus seizures—an obstetric emergency.
HELLP syndrome: Hemolysis, Elevated Liver enzymes, and Low Platelets. A severe, rapidly evolving form of preeclampsia that requires urgent care (Mayo Clinic; Johns Hopkins Medicine).

Who’s More at Risk in Late Pregnancy: High and Moderate Risk Factors

Preeclampsia can happen to anyone, but certain factors raise risk (Mayo Clinic; ACOG):

High risk:

Prior preeclampsia (especially early or severe)
Carrying multiples (twins or more)
Chronic conditions: high blood pressure, kidney disease, diabetes
Autoimmune disease (e.g., lupus, antiphospholipid syndrome)

Moderate risk:

First pregnancy
Age 35 or older
Family history of preeclampsia
Higher body mass index (obesity)
Certain pregnancy history (e.g., prior low-birth-weight baby)

If you have high or multiple moderate risks, your clinician may recommend low-dose aspirin during pregnancy to reduce risk (often started between 12–28 weeks, ideally before 16 weeks) (ACOG; CDC).

Red-Flag Warning Signs You Should Never Ignore

While some preeclampsia symptoms can overlap with normal pregnancy discomforts, the following are red flags—especially if they are new, worsening, severe, or occur together (Mayo Clinic; Johns Hopkins Medicine):

Severe or persistent headache that doesn’t improve with rest or acetaminophen
Vision changes: blurred vision, seeing spots, light sensitivity, or temporary loss of vision
Pain in the right-upper abdomen (under the ribs) or shoulder pain
Shortness of breath or difficulty breathing (possible fluid in the lungs)
Sudden swelling of the face, hands, or around the eyes
Nausea or vomiting (especially new in the third trimester)
Sudden weight gain (e.g., more than normal for you over a short time)

If you have severe symptoms—especially severe headache, vision changes, chest pain, shortness of breath, right‑upper abdominal pain, confusion, or any sign of a seizure—seek emergency care immediately.

Other Signs and What They May Mean

Some signs of preeclampsia are found during checkups or lab tests (Mayo Clinic):

Elevated blood pressure (140/90 mm Hg or higher)
Protein in urine (proteinuria)
Low platelets (thrombocytopenia)
Rising liver enzymes (liver stress) or elevated creatinine (kidney stress)

What about swelling? Mild swelling of the feet and ankles is common in late pregnancy. Sudden swelling of the face or hands, or rapid weight gain, is more concerning—especially with other symptoms. Preeclampsia signs often cluster (e.g., high BP + headache + vision changes). Call your provider if you notice any sudden changes.

When to Call Your Provider vs. Go to the Emergency Department

Knowing exactly when to call can be stressful. Here’s practical guidance based on clinical recommendations (ACOG; Mayo Clinic):

Call your provider the same day if:

Your home blood pressure is 140/90 or higher on two readings at least 15 minutes apart
You notice mild but new symptoms (headache, swelling, nausea) that don’t improve
You have a history of preeclampsia and something feels off

Go to the emergency department (or labor & delivery) now if:

You have severe symptoms: severe headache, vision changes, shortness of breath, chest pain, right‑upper abdominal pain, confusion, or low urine output
Your blood pressure is 160/110 or higher (even once), especially with symptoms
You experience seizure activity or fainting

What to say when you call (helpful for “when to call your doctor pregnancy” planning):

Your gestational age (e.g., “I’m 32 weeks.”)
Your blood pressure readings (including time taken and cuff type)
All symptoms, when they started, and whether they’re getting worse
Any medications you’re taking (including low-dose aspirin)
Notes on fetal movement and any recent changes

If you can’t reach your provider and are worried, go to the nearest emergency department or labor & delivery unit.

How Preeclampsia Is Diagnosed: What to Expect at Evaluation

Evaluation typically includes (ACOG; Johns Hopkins Medicine):

Blood pressure checks and a review of your symptoms
Urine testing for protein (spot protein/creatinine ratio or 24‑hour collection)
Blood tests: platelets; liver enzymes (AST/ALT); kidney function (creatinine)
Fetal assessment: nonstress test (NST), ultrasound for growth and amniotic fluid, and Doppler studies if needed

Your team assesses whether you have preeclampsia with or without “severe features,” which guides monitoring and delivery timing.

Home Blood Pressure Checks: Step-by-Step

Monitoring at home empowers you and your care team (ACOG; CDC):

Choosing a cuff:

Use a validated automatic upper-arm monitor (wrist devices are less reliable)
Choose the correct cuff size for your arm; ask your clinic to verify fit
Bring your cuff to an appointment to compare readings with clinic equipment

Before you measure:

Avoid caffeine, exercise, and nicotine for 30 minutes beforehand
Empty your bladder
Sit quietly for 5 minutes, back supported, feet flat, legs uncrossed
Support your arm at heart level on a table or pillow

How to measure:

Place the cuff on bare skin; don’t talk during the reading
Take two readings 1 minute apart; record both
Measure at the same times daily (e.g., morning and evening)
Keep a log of readings and symptoms to share at visits

Common mistakes to avoid:

Wrong cuff size or wearing the cuff over clothing
Measuring while talking, moving, or with legs crossed
Using a wrist cuff (unless your clinician specifically recommends it)

When to recheck or call:

If a reading is unexpectedly high, rest 5 minutes and recheck
Follow the call/seek-care thresholds above if readings remain high or you have symptoms

Partner’s Role: Support, Advocacy, and Symptom Spotting

Partners and support people can make a meaningful difference:

Help track symptoms and BP readings; note patterns or changes
Drive to appointments or the hospital if severe symptoms occur
Be an advocate: ask questions, take notes, and clarify next steps
Support medication adherence, healthy meals, hydration, and rest
Reduce stress where possible: handle chores, arrange childcare, create a calm environment
Watch for postpartum symptoms too (see below)—the risk doesn’t end at birth

A simple, supportive script: “I’m here. Your symptoms matter. Let’s call the provider now.”

Treatment Options and Birth Planning in the Third Trimester

There’s no cure for preeclampsia except delivery. The goal is to balance your safety and your baby’s gestational age, often with close monitoring until delivery is safest (Mayo Clinic; Cleveland Clinic):

Monitoring: Frequent BP checks, lab tests, and fetal surveillance. Some people need hospital care.
Antihypertensive medication: To reduce the risk of stroke and protect organs. Common choices in pregnancy include labetalol and nifedipine; your clinician will individualize treatment (ACOG; Mayo Clinic).
Magnesium sulfate: Given during labor and shortly after birth to prevent seizures in those with preeclampsia—especially with severe features (Cleveland Clinic).
Corticosteroids: If early delivery is likely before 34 weeks, steroids may be given to help mature the baby’s lungs (Mayo Clinic).
Timing of delivery: Many with preeclampsia without severe features are recommended to deliver around 37 weeks. With severe features, delivery may be recommended at 34 weeks or sooner if blood pressure can’t be controlled or organ complications develop (ACOG; Mayo Clinic).

Collaborate on a plan that covers where you’ll deliver, what to bring, and how to recognize worsening symptoms between visits.

After Delivery: Postpartum Preeclampsia and Recovery

Preeclampsia can appear after birth, usually within 48 hours but up to 6 weeks postpartum (CDC; Cleveland Clinic). Don’t ignore new symptoms after delivery—postpartum preeclampsia is an emergency.

Call your provider or seek emergency care for:

Severe headache, vision changes, right‑upper abdominal pain
Shortness of breath or chest pain
Blood pressure 160/110 or higher
New swelling of face/hands or sudden weight gain
Nausea/vomiting or feeling unwell

Postpartum care steps (CDC; ACOG):

Attend early BP checks and postpartum visits as scheduled
Continue BP meds and magnesium (if prescribed) as directed; many options are compatible with breastfeeding
Keep a home BP log for the first weeks postpartum
Ask for a personalized follow-up plan for blood pressure and heart health

Looking Ahead: Long-Term Heart and Kidney Health

A history of preeclampsia raises the risk of future chronic hypertension, heart disease, stroke, and kidney disease—often years after pregnancy (peer‑reviewed studies, PMC). Offspring of pregnancies affected by preeclampsia may also have higher risks of hypertension and metabolic challenges later in life (PMC).

Protective steps for you (ACOG; PMC):

Schedule a primary care follow-up within a few months postpartum to review BP, cholesterol, glucose, and kidney function
Maintain a heart-healthy lifestyle: balanced nutrition, movement as cleared by your clinician, sleep, and stress support
Know your numbers: aim for optimal BP and discuss individualized targets and medications
Share your pregnancy history with all future healthcare providers—it informs your long-term prevention plan

Protective steps for your child:

Keep up with pediatric visits and growth checks
Ask your child’s clinician about age-appropriate blood pressure monitoring and healthy lifestyle habits as they grow

The Bottom Line

Recognizing preeclampsia warning signs in the third trimester—and after birth—can be lifesaving. If you have severe symptoms or very high blood pressure, go to the emergency department. Otherwise, call your provider the same day to discuss what you’re experiencing. With timely diagnosis, monitoring, and a thoughtful birth plan, most families do well.

If you’re worried right now, don’t wait. Call your provider or head to labor & delivery. Your concerns are valid, and help is available.

Sources

ACOG – Preeclampsia and High Blood Pressure During Pregnancy: https://www.acog.org/womens-health/faqs/preeclampsia-and-high-blood-pressure-during-pregnancy
Mayo Clinic – Preeclampsia: Symptoms & Causes and Diagnosis & Treatment: https://www.mayoclinic.org/diseases-conditions/preeclampsia/symptoms-causes/syc-20355745; https://www.mayoclinic.org/diseases-conditions/preeclampsia/diagnosis-treatment/drc-20355751
Cleveland Clinic – Preeclampsia Overview: https://my.clevelandclinic.org/health/diseases/17952-preeclampsia
Johns Hopkins Medicine – Preeclampsia: https://www.hopkinsmedicine.org/health/conditions-and-diseases/preeclampsia
CDC – High Blood Pressure During Pregnancy: https://www.cdc.gov/high-blood-pressure/about/high-blood-pressure-during-pregnancy.html
PMC – Pathophysiology and Long-term Risks: https://pmc.ncbi.nlm.nih.gov/articles/PMC3148420/; https://pmc.ncbi.nlm.nih.gov/articles/PMC7311709/