What is preeclampsia?
Preeclampsia is a pregnancy complication that causes high blood pressure, kidney damage, and other problems. It's a potentially life-threatening condition that affects about 5 percent of pregnant women in the United States.
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, but it can happen at any time in the second half of pregnancy, during labor, or even up to six weeks after delivery.
How can preeclampsia affect me and my baby?
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 reduced blood flow can affect your liver, kidneys, brain, and other delicate organs.
- When less blood flows to the uterus, it can cause problems for a baby, such as poor growth, too little amniotic fluid, and 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.
- If not well managed, preeclampsia can lead to very serious complications such as eclampsia (marked by seizures) and HELLP syndrome, which affects the blood and liver.
- Preeclampsia is known to raise your risk of heart disease later in life.
Preeclampsia signs and 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 one, 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.
If you have any of these warning signs of severe preeclampsia or HELLP syndrome:
- Severe or persistent headache
- Vision changes, including double vision, blurriness, seeing spots or flashing lights, light sensitivity, or temporary vision loss
- Intense pain or tenderness in your upper abdomen
- Difficulty breathing
What is HELLP syndrome?
This is a life-threatening condition that develops in 4 to 12 percent of women with preeclampsia. Some women develop HELLP without a preeclampsia diagnosis, so some experts think it’s a variation of preeclampsia.
HELLP stands for:
- Hemolysis (the breakdown of red blood cells)
- Elevated liver enzymes
- Low platelets (the blood cells that are necessary for clotting)
What is eclampsia?
In rare situations, preeclampsia can lead to seizures, a condition called eclampsia. Eclampsia can be life-threatening for both you and your baby.
The seizures may be preceded by symptoms such as:
- Severe or persistent headache
- Vision changes, including blurred vision, seeing spots, or sensitivity to light
- Mental confusion
- Intense upper abdominal pain
What causes preeclampsia?
Experts believe that preeclampsia is caused by a reduced blood flow to the placenta, and that many cases actually begin early in pregnancy, well before any symptoms become evident. This could happen if the placenta fails to implant properly in the lining of the uterus, and the arteries in that area don't dilate as they should, meaning less blood reaches the placenta. Conditions such as chronic hypertension and diabetes can also cause reduced blood flow to the placenta.
There's also evidence that changes in blood flow to 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)
- Reduced blood volume
- Changes in blood clotting
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 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 of preeclampsia
- Being obese (having a body mass index of 30 or more)
- Carrying twins or more
- Being younger than 20 or older than 35
- Having in vitro fertilization (IVF)
Certain health conditions 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
If you're at risk for preeclampsia, your provider may schedule more frequent prenatal visits in your third trimester to monitor you closely.
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.
- High blood pressure. Your blood pressure is considered high if you have a systolic reading of 140 or greater (the upper number) 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.
- Protein in urine. 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 an ultrasound to check your baby's growth, if you haven’t had one recently, and possibly a biophysical profile or nonstress test to see how your baby's doing.
If you’re diagnosed with preeclampsia, you and your baby will be monitored closely for the rest of your pregnancy.
How is preeclampsia treated?
You'll be given medication to lower your blood pressure if it's extremely high.
If you have severe preeclampsia, you'll 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.
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.
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 (technically called "preeclampsia with severe features"), 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.
The only way to “treat” preeclampsia is by delivering the baby. You'll be induced or delivered by c-section if your preeclampsia is getting worse or your baby isn't thriving, regardless of where you are in your pregnancy.
If your condition is stable:
- If you're not yet at 37 weeks, your preeclampsia is not severe, and your baby's in good condition, you probably won't need to deliver right away. You might remain in the hospital so you can be monitored. Or you might be sent home where you may have to monitor your blood pressure.
- If you're at 37 weeks or more, you'll likely be induced, especially if your cervix is starting to thin out and dilate. (You'll have a c-section if there are signs that you or your baby won't be able to tolerate labor.)
If you or your baby are not doing well:
- If you're at 34 weeks or later you may be induced or, in certain situations, delivered by c-section.
- If you're not yet 34 weeks along, you may be given corticosteroids to help your baby's lungs mature more quickly. If you don't deliver immediately, both you and your baby will be monitored very closely.
After delivery, you'll remain under close supervision for a few days. Most women, especially those with less severe preeclampsia, see their blood pressure start to go down in a day or so. In severe cases, it can remain elevated for longer.
If your blood pressure remains high, 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.)
What if I develop preeclampsia after delivery?
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.
Can you prevent preeclampsia?
Low-dose aspirin therapy may prevent preeclampsia. According to guidelines, high-risk women may start taking low-dose aspirin after 12 weeks of pregnancy. Ask your provider if this is right for you — never take aspirin during pregnancy unless your provider advises it.
Other than that, the best thing you can do is get good prenatal care and keep all your appointments. At each visit, your healthcare provider will check your blood pressure. It's also important to know the warning signs of preeclampsia so you can alert your provider and start treatment as soon as possible.
If you’re not pregnant, you can try to reduce your risk by reaching a healthy weight and keeping your blood pressure in check. If you have any chronic conditions that raise your risk, such as diabetes or lupus, work with your doctor to manage it as well as possible before you get pregnant.
Find out more about preeclampsia
Call the Preeclampsia Foundation at (800) 665-9341 or visit preeclampsia.org.
Visit the Society for Maternal-Fetal Medicine's website for more information and to find an MFM specialist near you.