Preeclampsia: Signs, causes, risk factors, and treatment

What is preeclampsia?

Preeclampsia is a serious high blood pressure disorder that happens during pregnancy or soon after childbirth. It's a potentially life-threatening condition that affects about 5 percent of pregnancies in the United States. With proper care, most pregnant women with preeclampsia have healthy babies and stay healthy themselves.

Preeclampsia may not cause any noticeable symptoms but can still be very dangerous for you and your baby, even if you feel fine. Your healthcare provider will screen you for the condition at every prenatal visit by taking your blood pressure, and, if it's high, testing your urine for protein.

Preeclampsia most commonly develops during the last trimester. (Ninety percent of cases occur at 34 weeks or later), but it can happen at any time after 20 weeks, during labor, or even up to six weeks after delivery. When it develops before 34 weeks it's called early-onset preeclampsia.

What causes preeclampsia?

Experts believe that preeclampsia is caused by abnormal blood flow within the placenta. In many women, the roots of their preeclampsia stretch back to the early days of their pregnancy.

Preeclampsia is a disease of abnormal blood vessels. The placenta learns to grow from signals from maternal circulation. If a mom's blood vessels have damage – from long-term diabetes or chronic hypertension, for example – they will "teach" this damage to the growing placenta, increasing the risk of preeclampsia.

There's also evidence that changes in blood flow within the placenta trigger the release of high levels of certain placental proteins into your bloodstream. This can set off a complex chain of reactions that includes:

• Constricted blood vessels, leading to high blood pressure
• Damage to the vessel walls, leading to swelling and protein in your urine
• Kidney and liver damage, leading to pain and reduced urine output
• Dramatic drop in platelets, leading to a difficulty clotting normally and a potential increase in your blood loss during delivery
• Swelling around your brain, leading to headaches and/or seizures
• Reduced blood flow to your baby, leading to growth restriction or low amniotic fluid

Why this happens to some women and not others isn't fully understood, and there's probably no single explanation. Genetics, nutrition, certain underlying diseases, the way your immune system reacts to pregnancy, and other factors may all play a role.

Preeclampsia symptoms

Preeclampsia doesn't always cause noticeable symptoms, especially in the early stages, and symptoms can also vary from woman to woman. Some signs of preeclampsia – such as swelling, nausea, and weight gain – may seem like normal pregnancy complaints, so it's important to be aware of any potential warning signs.

Unusual swelling is the most common symptom of preeclampsia, so call your healthcare provider if you:

• Notice swelling in your face or puffiness around your eyes
• Have more than slight swelling in your hands
• Have sudden or excessive swelling of your feet or ankles
• Gain more than 4 pounds in a week (often a result of water retention)

Note: Not all women with preeclampsia have obvious swelling or dramatic weight gain, and not all women with swelling or rapid weight gain have preeclampsia.

Preeclampsia complications

Most women who get preeclampsia develop it near their due dates and do fine with proper care. But the earlier you have it, and the more severe it is, the greater the risks for you and your baby.

Here's what can happen:

• High blood pressure and preeclampsia can affect your liver, kidneys, eyes, and other body systems.
• Severe high blood pressure in pregnancy can cause a stroke.(Strokes happen at much lower blood pressures during pregnancy.)
• Abnormal blood flow in the uterus can cause complications for your baby, such as poor growth and too little amniotic fluid.
• Uncontrolled hypertension can lead to placental abruption (when the placenta separates from the uterine wall before delivery).
• You may need to deliver early if the condition is severe or getting worse. In this case your baby may suffer effects of prematurity. Fifteen percent of premature births in the United States are due to preeclampsia.
• In some cases, preeclampsia can lead to very serious complications such as eclampsia (marked by seizures) and HELLP syndrome. HELLP stands for Hemolysis (the destruction of red blood cells), Elevated Liver enzymes, and Low Platelet count.
• Preeclampsia is linked to future heart and cardiovascular disease, especially if you've had it more than once or have had preterm preeclampsia. (Experts aren't sure if this is because people who get preeclampsia are also likely to get heart disease or if preeclampsia increases the risk of heart disease.)

Preeclampsia risk factors

It's more common to get preeclampsia during a first pregnancy. However, once you've had preeclampsia, you're more likely to develop it again in later pregnancies. The more severe the condition and the earlier it appears, the higher your risk.

• If you had preeclampsia at the very end of your previous pregnancy, the chance of it happening again is fairly low – about 13 percent.
• If you developed severe preeclampsia before 29 weeks of pregnancy, your chance of getting it again may be 40 percent or even higher.
• If you had preeclampsia in two previous pregnancies, your risk of getting it in a third is about 30 percent.

Other risk factors for preeclampsia include:

• Having a family history (mother or sister) of preeclampsia
• Being obese (having a body mass index of 30 or more)
• Being African American
• Carrying twins or more
• Being younger than 20 or older than 35
• Having in vitro fertilization (IVF)
• Having a history of stillbirth

Certain health conditions may also make it more likely you'll develop preeclampsia. These include:

• Chronic hypertension or gestational hypertension
• Certain blood clotting disorders, such as thrombophilia or antiphospholipid syndrome
• Diabetes or kidney disease
• Autoimmune diseases, such as lupus
• Periodontal disease

If you're at risk for preeclampsia, your provider may schedule more frequent prenatal visits in your third trimester to monitor you closely. You'll likely be asked to monitor your blood pressure at home, too.

How is preeclampsia diagnosed?

Your healthcare provider will check for high blood pressure and protein in your urine and may order more tests as well, such as:

• Blood pressure checks. Your blood pressure is considered high if you have a systolic reading of 140 or greater (the upper number in the reading) or a diastolic reading of 90 or higher (the lower number). Because blood pressure changes during the day, you'll have more than one reading to confirm that it's consistently high.
• Urine tests for protein. You may have a one-time test that checks the protein-to-creatinine ratio (creatinine is a waste product that your kidneys should filter out). Or you may need to collect all your urine for 24 hours to check the total protein.
• Blood tests. If preeclampsia is a concern, your provider will order regular blood tests, including complete blood counts (CBC) and tests for liver and kidney function. These also screen for HELLP syndrome.
• Tests of baby's health. You'll likely have ultrasounds to monitor your baby's growth and amniotic fluid, and possibly a biophysical profile or nonstress test to see how your baby's doing.

Preeclampsia treatment

If you're diagnosed with preeclampsia, you and your baby will be monitored closely for the rest of your pregnancy.

Medication

If your blood pressure is extremely high, you'll be given medication immediately to lower it. If it's not extremely high, you may or may not be given medication, depending on how close you are to delivering your baby.

If you have preeclampsia with severe features, you'll also be given an IV medication called magnesium sulfate. This is to prevent eclampsia (seizures). Magnesium sulfate can have unpleasant side effects in some women, including nausea, flu-like symptoms, fatigue, and thirst, but it's an important part of the treatment of preeclampsia to reduce your serious risk of seizures.

Rest

Some providers may recommend restricting your activities because your blood pressure will generally be lower when you're taking it easy. But complete bedrest, in which you're confined to bed for an extended period, raises your risk of blood clots and isn't recommended.

Hospitalization

If at any time your symptoms indicate that your condition is getting severe, or that your baby isn't thriving, you'll be admitted to the hospital and will probably need to deliver early. It's not unusual for preeclampsia to become more severe during delivery, so you'll be monitored very closely throughout the birth.

If you're diagnosed with severe preeclampsia, you'll have to spend the rest of your pregnancy in the hospital. You may be transferred to a hospital where a high-risk pregnancy specialist can care for you.

Delivery

The only way to "treat" preeclampsia is by delivering your baby. Unless your condition or your baby's condition is so fragile that immediate delivery is needed, a c-section isn't required.

You'll probably be induced if any of the following happen:

• You're at 37 weeks or more, especially if your cervix is starting to thin out and dilate
• Your preeclampsia is getting worse
• Your baby isn't thriving

If you and your baby are doing fine, you're not yet at 37 weeks, and your preeclampsia isn't severe, you may remain in the hospital so you can be monitored. Or you may be sent home, where you may have to monitor your blood pressure.

You may be given corticosteroids to help your baby's lungs mature more quickly. (Steroids are not given to women who are diabetic and over 34 weeks, however).

After delivery

After delivery, you'll remain under close medical supervision for a few days. Most women, especially those with non-severe (or "mild") preeclampsia, see their blood pressure start to go down in a day or so.

In many cases, though, blood pressure can remain elevated for longer. Or it may go down right after delivery but start to go up again by 3 to 5 days postpartum. If either is the case for you, you'll be given blood pressure medication for a few weeks to months. You'll be asked to check your blood pressure at home and to make follow-up blood pressure appointments with your provider in the days and weeks following your delivery.

If you have severe preeclampsia, you'll probably be given magnesium sulfate intravenously for at least 24 hours after delivery to prevent seizures. (You may also need to take blood pressure medication at home.)

Postpartum preeclampsia

If you develop preeclampsia during or after labor, you'll be monitored closely. Depending on your situation, you may be given magnesium sulfate to prevent seizures and medication to reduce your blood pressure.

Sometimes cases of preeclampsia, eclampsia, and HELLP syndrome develop after delivery, usually within the first 48 hours but as late as six weeks after delivery.

You'll likely have a follow-up blood pressure check within one week of discharge from the hospital, but if you start to experience any symptoms of preeclampsia or HELLP, such as a severe headache, a pain high up in your abdomen, or changes to your vision, contact your healthcare provider right away.

How to prevent preeclampsia

To reduce your risk of developing preeclampsia, your provider may recommend that you try:

• Low-dose aspirin therapy. Currently this is considered the best prevention for preeclampsia and is recommended for anyone at risk. According to guidelines from the American College of Obstetricians and Gynecologists, high-risk women may start taking low-dose aspirin after 12 weeks of pregnancy. Ask your provider if this is right for you – and never take aspirin during pregnancy unless your provider advises it.
• Vitamin D supplementation. Some studies point to a link between vitamin D and a lowered risk of preeclampsia, but other studies don't support this link. Your healthcare provider may check to make sure that you're not deficient in vitamin D.
• Calcium supplements. For women who were deficient in calcium before pregnancy, a calcium supplement might be preventative for preeclampsia. But some experts say that women in developed countries are unlikely to have a calcium deficiency severe enough to benefit from this.

You'll also want to:

• Get good prenatal care. Schedule and keep all your appointments. At each visit, your healthcare provider will check your blood pressure.
• Know the warning signs. Understanding the symptoms of preeclampsia means you can alert your provider and start treatment as soon as possible.

If you're not pregnant yet, you can reduce your risk of preeclampsia by:

• Maintaining a healthy weight
• Keeping your blood pressure in check
• Working with your doctor to manage any chronic conditions that raise your risk, such as diabetes or lupus
• Going to the dentist regularly. There's some evidence that periodontal disease may be linked to an increased risk for preeclampsia.

Find out more about preeclampsia

Call the Preeclampsia Foundation at (800) 665-9341 or visit preeclampsia.orgOpens a new window.

Visit the Society for Maternal-Fetal Medicine's websiteOpens a new window for more information and to find an MFM specialistOpens a new window near you.

Learn more:

• Pregnancy symptoms you should never ignore
• Prenatal tests: An overview
• The ultimate pregnancy to-do list: Third trimester