Preeclampsia is a potentially life-threatening form of hypertension that can occur during the second half of pregnancy. In addition to high blood pressure, a pregnant person with preeclampsia also has protein in her urine. If left untreated, the condition can lead to serious complications, such as seizures (eclampsia), stroke, and/or maternal or fetal death.
Between 2% and 7% of pregnant women develop preeclampsia. It commonly occurs in the third trimester (after 34 weeks of pregnancy) but may be diagnosed as early as the 20th week of pregnancy.
Women who develop high blood pressure without protein in their urine after 20 weeks of pregnancy have a condition known as gestational hypertension. In up to 50% of cases, gestational hypertension advances to preeclampsia.
Treatments are available to help manage preeclampsia with the goal of preventing complications and, if possible, reaching term. However, the condition typically resolves only after delivery.
What is preeclampsia?
Preeclampsia is a form of hypertension that affects women in the second half of pregnancy. By definition, the condition also involves the presence of protein in the urine above a certain threshold.
Each time a pregnant woman sees her doctor for a prenatal visit, her blood pressure is checked. Blood pressure readings contain two numbers: The top number, or systolic blood pressure, measures the pressure exerted on the inside of the arteries when the heart contracts or beats. The bottom number, or diastolic blood pressure, measures the pressure exerted on the inside of the arteries when the heart relaxes or rests between heartbeats.
The normal range for blood pressure readings is 120/80 mmHg or lower. Blood pressure readings of 140/90 mmHg or higher on two separate occasions that are more than four hours apart after 20 weeks gestation, coupled with protein in the urine (proteinuria) above a certain cut-off lead to a diagnosis of preeclampsia. Without protein in the urine, newly diagnosed high blood pressure after 20 weeks gestation is known as gestational hypertension. Elevated blood pressure prior to 20 weeks, with or without protein in the urine, suggest chronic hypertension.
Preeclampsia is associated with a narrowing of the small arteries across the body, leading to organs malfunction. In the kidneys, this presents as leakage of protein and, in severe cases, decreased renal function. The small blood vessels (capillaries) across the body are also unable to prevent fluid leakage. This may result in generalized swelling and, in severe cases, fluid accumulation in the lungs, making it difficult to breathe. Seizures or stroke may be signs of brain malfunction.
Preeclampsia can be dangerous for both pregnant people and their developing babies. It may lead to complications such as:
- Placenta detaching from the uterine wall (abruption)
- Slowed growth of the fetus due to fewer nutrients traveling through the umbilical cord (fetal growth restriction)
- Decreased levels of amniotic fluid surrounding the baby in utero (oligohydramnios)
- Delivering prematurely (before 37 weeks) to prevent severe complications for the pregnant person and/or the fetus.
- Kidney or liver damage
- Seizures or stroke
- Coagulation problems
- Maternal and/or fetal death
Sometimes preeclampsia advances to more serious conditions, including:
- Eclampsia, which involves pre-eclampsia and seizures
- HELLP syndrome (preeclampsia with Hemolysis, Elevated Liver enzyme levels, and Low Platelet levels), a form of severe pre-eclampsia associated with the destruction of red cells (hemolysis), abnormal liver function, and decreased platelets—the cells responsible for clotting.
What causes preeclampsia?
The exact cause of preeclampsia is unknown. It is likely related to abnormalities in the placental development taking place early in the pregnancy, leading to a lack of the normal dilation (enlargement) of the small arteries in the placenta, and reduced blood flow to the placenta, fetus, and pregnant woman’s organs.
Certain conditions increase a person’s risk of developing preeclampsia, such as:
- A personal or family history of preeclampsia
- Carrying twins or other multiple gestation
- Chronic hypertension
- Lupus or other autoimmune diseases
- Kidney disease
- Sleep apnea
- A first pregnancy
- Being overweight or obese
- Being over age 35
- In-vitro fertilization (IVF)
- Becoming pregnant again after 10 or more years
- Previously delivering a low-birthweight baby
What are the possible symptoms of preeclampsia?
A pregnant woman with preeclampsia may experience the following symptoms:
- Swollen face, hands, and/or feet
- Persistent headache that does not respond to acetaminophen
- Vision problems, such as seeing spots or blurry vision
- Pain in the upper abdomen, on the right side in particular
- Heartburn-like symptoms
- Shoulder pain
- Nausea and/or vomiting (unrelated to morning sickness early in pregnancy)
- Decreased amount of urine
- Trouble breathing
- Sudden, excessive weight gain
How is preeclampsia diagnosed?
Preeclampsia is typically diagnosed during the third trimester of pregnancy at a routine prenatal visit.
It’s important to tell your doctor if you or anyone in your family has had preeclampsia or gestational hypertension during a previous pregnancy.
If your blood pressure reading is 140/90 mmHg or higher and you have protein in your urine, you will be diagnosed with preeclampsia. The condition is considered to be severe if your blood pressure is 160/110 mmHg or higher or if you have other symptoms or abnormal blood work.
You may be offered other diagnostic tests to check the function of your liver, kidneys, and coagulation system. The well-being (growth) of the fetus will also be tested by ultrasound and fetal heart rate monitoring.
How is preeclampsia treated?
Pre-eclampsia will be managed differently based on its severity and gestational age at diagnosis.
For mild preeclampsia, one or more of the following treatments may be recommended:
- Blood pressure readings weekly or twice weekly
- Frequent urine tests to check for protein
- Monitoring “kick counts,” or fetal movement
- Weekly blood tests to look at blood platelets, liver enzymes, and kidney function;
- Ultrasounds every 2 to 4 weeks to monitor fetal growth to ensure the baby is growing at the expected rate
- Delivery at 37 weeks of pregnancy (delivery is considered the best treatment as symptoms resolve within a few days/weeks afterwards)
Blood pressure medication is not recommended for patients with non-severe preeclampsia, but may be for those with severe preeclampsia based on their blood pressure levels. The most common medications used for blood pressure control are labetalol, nifedipine, and methyldopa.
For severe preeclampsia, one or more of the following treatments may be recommended:
- Hospitalization for close monitoring and treatment
- Medications to treat hypertension, such as labetalol, hydralazine, nifedipine
- Magnesium sulfate to prevent seizures (this is only used when a decision to deliver is made)
- Early delivery (at 34 weeks of pregnancy); oxytocin may be used to induce labor
- Corticosteroids to help the baby’s lungs mature more quickly if delivery is scheduled at 34 weeks or before
Preeclampsia sometimes occurs after delivery (postpartum). Health care providers will closely monitor a patient’s blood pressure readings for three days after delivery, particularly if they had high blood pressure during pregnancy or labor, or if they experience headaches and vision problems after delivery.
What is the outlook for people with preeclampsia?
Preeclampsia usually resolves within 6 weeks of delivery. Occasionally, high blood pressure doesn’t resolve after pregnancy, indicating the condition has developed into chronic hypertension.
Women with preeclampsia during pregnancy are twice as likely to develop heart disease or stroke later in life. They are also at increased risk of having preeclampsia again in future pregnancies. In addition, children whose mothers had preeclampsia during their pregnancies are at increased risk of preterm birth and respiratory distress syndrome, highlighting the importance of regular prenatal appointments to monitor and treat the condition.
What makes Yale unique in its treatment of preeclampsia?
"One of our department’s first Care Signature clinical care pathways was for acute hypertension in pregnancy, which has allowed us to standardize our approach to diagnosis and timely treatment when we have a patient with elevated blood pressures,” says high-risk pregnancy specialist France Galerneau, MD. “The care pathways provide an electronic algorithm embedded into the electronic health record that allows the right care to happen at the right time, making it easier for providers to find the correct orders and provide the best evidence-based care with ease.”
Additionally, the Maternal In Reach Team for Equity (MITEY) program at Yale New Haven Hospital [YNHH] provides postpartum blood pressure monitoring, evaluation, treatment, education and support to patients who experienced hypertension disorder [high blood pressure] during pregnancy and delivered at, or were transferred to YNHH,” she adds. “Patients can begin the program during their 4th trimester [postpartum period],” she says.
Appointments are available with MITEY team members Mondays through Fridays, between 7:30 a.m. – 4 p.m. Telehealth or in-person appointments are available.
More information can be found here.
The MITEY program is found under “Project Mothercare” in the “Maternity Resources” section of the page.