Stroke & Pregnancy: The Silent Threat of Preeclampsia

9 high blood pressure risk factors to know.
Pregnant patient gets blood pressure checked

Mary Hegarty felt as healthy as ever during her first pregnancy.

A couple of weeks before her due date, Hegarty and her husband planned an afternoon boat ride. On their way to the lake, with a motorboat in tow, the couple first stopped by the hospital for a routine obstetrics appointment.

The boat never made it to the water. Hegarty was diagnosed with preeclampsia, a condition that causes dangerously high blood pressure.

“The diagnosis was a big surprise because I was feeling great,” Hegarty recalls, adding that she was 29 at the time of diagnosis. “And up until then, I never had issues with high blood pressure.”

Hegarty was given a medication to help soften the cervix and nudge her body into labor overnight. If it didn’t work, she would be induced the next day. Fortunately, a healthy baby boy arrived at 10:30 a.m. without further intervention.

“Between the time I was diagnosed and when he was delivered, naturally my biggest fear was for my son’s health,” Hegarty says. “I was also a little concerned about having a stroke, but only once I learned that was an associated risk. I was very fortunate because I had great health care, and everything turned out fine.”

Hypertension, also known as high blood pressure, during pregnancy can place extra stress on your heart and kidneys, leading to heart disease, kidney disease and stroke.

Stroke in pregnancy is relatively rare, but preeclampsia and other hypertension disorders are more common during pregnancy and in the six weeks after childbirth.

“During pregnancy, your body gradually changes week by week,” says Marjorie Meyer, MD, an obstetrician and maternal fetal medicine physician at University of Vermont Medical Center. “But after delivery, your body goes through a gigantic change all at once. That’s why you can still experience hypertension disorders in those early postpartum weeks.”

Blood Pressure Changes During and After Pregnancy

Blood pressure tends to be at its lowest between 16 and 20 weeks gestation. Near the end of pregnancy, blood pressure rises to the body's pre-pregnancy levels.

It then peaks three to six days after delivery, regardless of whether someone experienced high blood pressure during pregnancy.

That postpartum spike can be caused by medications, extra fluid intake during postpartum or by blood vessels returning to their pre-pregnancy size.

Are You at Risk for High Blood Pressure During Pregnancy?

As Hegarty experienced, preeclampsia and other hypertension disorders don’t always come with symptoms.

“High blood pressure and preeclampsia can come out of the blue,” Dr. Meyer says.

Risk factors for hypertension during pregnancy include:

  • Obesity
  • Diabetes
  • Being age 35 or older
  • Being pregnant for the first time
  • Expecting twins (or triplets)
  • High cholesterol
  • A personal or family history of high blood pressure
  • Chronic hypertension before pregnancy
  • Certain pre-existing medical conditions, including autoimmune diseases

Different Types of Hypertension

Not all hypertension disorders are alike. Their severity can range from mild to life-threating.

  • Chronic hypertension: Also known as high blood pressure, is present before a person becomes pregnant or when the condition develops earlier in pregnancy, before 20 weeks. 
  • Gestational hypertension: When a pregnant person develops high blood pressure in the second half of pregnancy, after 20 weeks.
  • Preeclampsia: Happens when high blood pressure develops after 20 weeks of pregnancy. Preeclampsia puts stress on the heart and other organs and can cause complications like restricting the blood supply to the placenta and damaging the kidneys. Preeclampsia can require early delivery.
  • Eclampsia: Rare but life-threatening complication of preeclampsia that can trigger seizures because of untreated or undertreated preeclampsia.
  • HELLP syndrome: Rare and severe type of preeclampsia. HELLP (preeclampsia with Hemolysis, Elevated Liver enzyme levels, and Low Platelet levels), which causes liver damage and destroys red blood cells and platelets, can require an early delivery.

Your Risk of Stroke Increases During and Shortly After Pregnancy

The chance of having a stroke when you are pregnant is about three times higher than the risk for other adults of the same age. Stroke occurs in about 30 of every 100,000 pregnancies.

The risk for stroke is highest in the last month before delivery and in the first six weeks after giving birth.

“Younger patients are having more stroke complications and we’re seeing a greater number of pregnant patients who are obese, have diabetes or chronic hypertension,” says Daniela Zambrano, MD, a vascular neurologist at UVM Medical Center. 

In 2020, Dr. Zambrano published research about maternal stroke, highlighting how pregnant women from minority groups in the United States experienced higher stroke risk during delivery admissions compared with non‐Hispanic whites.

“Those higher rates are related to lack of access to prenatal care and not being treated for high blood pressure,” she says.

That’s why it's vital for patients to receive regular prenatal check-ups and to listen to their bodies.

“Pay attention to symptoms and call 911 if something doesn’t feel right,” Dr. Zambrano says. “It can save your life – and your baby’s.”

Recognize a Stroke Using the Acronym B.E.F.A.S.T

Symptoms of a stroke include headache, loss of balance and numbness. Zambrano suggests using the B.E.F.A.S.T. checklist to recognize a stroke.

BEFAST stroke signs infographic

B - Balance: Watch for sudden loss of balance
E - Eyes: Check for vision loss
F - Face: Look for an uneven smile
A - Arm: Check if one arm is weak
S - Speech: Listen for slurred speech
T - Time: Call 9-1-1 right away

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