What is preeclampsia?
Preeclampsia is a serious condition that affects about 5 percent of pregnant women and typically starts after 20 weeks of pregnancy. Elevated blood pressure is the primary symptom, but there may be others such as protein in the urine, or liver or kidney abnormalities.
The condition most commonly shows up after you've reached 37 weeks, but it can develop any time in the second half of pregnancy, including during labor or even after delivery (usually in the first 48 hours).
It's possible to have symptoms of preeclampsia before 20 weeks, but only in rare cases, such as with a molar pregnancy.
Preeclampsia can range from mild to severe, and it can progress slowly or rapidly. Your doctor will screen you for the condition at every prenatal visit by taking your blood pressure and checking your urine sample for protein.
How can preeclampsia affect my health and my baby's health?
The more severe the condition and the earlier it appears, the greater the risks for you and your baby. Most women who get preeclampsia develop a mild version near their due date, and they and their babies do fine with proper care.
But when preeclampsia is severe, it can affect many organs and cause serious or even life-threatening problems. That's why you'll need to deliver early if your condition is severe or getting worse.
Preeclampsia causes the blood vessels to constrict, resulting in high blood pressure and a reduced blood flow that can affect organs in your body, such as your liver, kidneys, and brain.
When less blood flows to your uterus, it can mean problems for your baby, such as poor growth, too little amniotic fluid, and placental abruption (when the placenta separates from the uterine wall before delivery). In addition, your baby may suffer the effects of prematurity if you need to deliver early to protect your health.
Changes in your blood vessels caused by preeclampsia may cause your capillaries to "leak" fluid into your tissues, which results in swelling (known as edema). And when the tiny blood vessels in your kidneys leak, protein from your bloodstream spills into your urine. (It's normal to have a small amount of protein in your urine, but more than a little bit can signal a problem.)
What is HELLP syndrome?
Some women with preeclampsia develop a condition called HELLP syndrome. HELLP stands for Hemolysis, the breakdown of red blood cells; Elevated Liver enzymes; and Low Platelets, the blood cells that are necessary for clotting.
HELLP syndrome puts you and your baby at an even higher risk for the same kinds of problems that can result from severe preeclampsia alone. Once you develop preeclampsia, you'll have your blood tested periodically for signs of HELLP syndrome.
What is eclampsia?
Infrequently, preeclampsia can lead to seizures, a condition called eclampsia. Eclampsia can have very serious consequences for both the mother and the baby.
The seizures may be preceded by symptoms such as severe or persistent headache, vision changes (blurred vision, seeing spots, or sensitivity to light), mental confusion, or intense upper abdominal pain. Sometimes, though, the seizures occur without warning. For this reason, all women with severe preeclampsia are given magnesium sulfate, an anti-seizure medication.
What are the symptoms of preeclampsia?
Preeclampsia can come on suddenly, so it's very important to be aware of the symptoms.
Call your doctor or midwife right away if you notice swelling in your face or puffiness around your eyes, more than slight swelling of your hands, or excessive or sudden swelling of your feet or ankles. This is caused by water retention that can also lead to rapid weight gain, so let your caregiver know if you gain more than 4 pounds in a week.
(Note that not all women with preeclampsia have obvious swelling or dramatic weight gain, and not all women with swelling or rapid weight gain have preeclampsia.)
With severe preeclampsia, you may experience other symptoms. Call your caregiver immediately if you have any of these warning signs:
- Severe or persistent headache
- Vision changes, including double vision, blurriness, seeing spots or flashing lights, light sensitivity, or temporary loss of vision
- Intense pain or tenderness in your upper abdomen
- Nausea and vomiting
Symptoms can vary from woman to woman, and preeclampsia can occur without any obvious symptoms, particularly in the early stages.
What's more, some symptoms of preeclampsia, such as swelling and weight gain, may seem like normal pregnancy complaints. So you might not know you have the condition until it's discovered at a routine prenatal visit. This is one of the reasons it's so important not to miss your appointments.
How is preeclampsia diagnosed?
Your practitioner will check your blood pressure and urine. If your blood pressure is elevated and you have protein in your urine, you'll be diagnosed with preeclampsia. (Even if you don't have protein in your urine, an elevated blood pressure reading may prompt your practitioner to order more lab tests.)
Your blood pressure is considered high if you have a systolic reading of 140 or greater or a diastolic reading of 90 or higher. Because blood pressure can fluctuate during the day, you'll have more than one reading to confirm that your blood pressure is consistently high.
A nurse will dip a test strip into your urine sample to look for protein. The amount of protein in your urine can also fluctuate during the day, so if your practitioner suspects that there's a problem, she may have you collect your urine for 24 hours so it can be tested.
What causes preeclampsia?
Researchers have learned a lot about preeclampsia in the last decade, but many aspects of the condition remain a mystery.
Experts believe that many cases of preeclampsia actually begin early in pregnancy, well before any symptoms become evident, and that they are related to reduced blood flow to the placenta.
This could happen if the placenta fails to implant properly in the lining of your uterus and the arteries in that area don't dilate as they should, so less blood gets to the placenta. Conditions such as chronic hypertension and diabetes can also cause reduced blood flow to the placenta.
There's evidence that changes in blood flow to the placenta may 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, and changes in blood clotting, which in turn can cause a host of other problems.
Why this occurs in some women and not others is not 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 play a role.
Does having high blood pressure before pregnancy put me at higher risk for preeclampsia?
Yes. If you're found to have high blood pressure before you conceive or during the first half of your pregnancy, you're considered to have chronic hypertension, and your practitioner will need to monitor you closely during your pregnancy to make sure that your blood pressure stays under control and that your baby is thriving. She will also watch for signs of preeclampsia and other complications.
Women with chronic hypertension who develop preeclampsia are at higher risk for complications than women with either condition alone.
What else puts me at high risk for preeclampsia?
It's more common to get preeclampsia for the first time 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 the risk. In fact, if you had severe preeclampsia that started before 30 weeks of pregnancy, your likelihood of getting it again may be as high as 40 percent. Other risk factors include:
- Having chronic hypertension
- Having certain blood clotting disorders, diabetes, kidney disease, or an autoimmune disease like lupus
- Having a close relative (a mother, sister, grandmother, or aunt, for example) who had preeclampsia
- Being obese (having a body mass index of 30 or more)
- Carrying two or more babies
- Being younger than 20 or older than 40
How is preeclampsia managed?
It depends on how severe it is, how far along you are, and how your baby's doing. You'll probably be hospitalized for an initial assessment – and possibly for the rest of your pregnancy.
In addition to blood pressure and urine testing, your practitioner will do a number of blood tests to find out how serious the problem is. You'll also have a sonogram to check your baby's growth, and possibly a biophysical profile and nonstress test to see how your baby's doing.
If you have mild preeclampsia and you're at 37 weeks or more, you'll likely be induced, especially if your cervix is starting to thin out and dilate. If there are signs that you or your baby won't be able to tolerate labor, you'll have a c-section.
If you're not yet at 37 weeks, your condition is mild and appears stable, and your baby's in good condition, you probably won't need to deliver right away. Instead, you might be sent home and told to take it easy. (You may be asked to monitor your blood pressure at home or have a nurse check on you.) Or your practitioner might want you to remain in the hospital so that you can be monitored more closely.
Although no studies show that bedrest improves the outcome for you or your baby when you have preeclampsia, your blood pressure will generally be lower when you're at rest. So most practitioners will recommend that you restrict your activities or go on modified bedrest.
(Complete bedrest, in which you're confined to bed for an extended period, is not recommended and would increase your risk for blood clots.)
Whether at home or in the hospital, you and your baby will be monitored closely for the rest of your pregnancy. If you're at home, this will mean coming in to see your practitioner for frequent blood pressure checks and urine tests (and possibly blood tests), as well as periodic sonograms and nonstress tests. You'll also do daily fetal kick counts.
If at any time your symptoms indicate that your preeclampsia is getting worse or that your baby isn't thriving, you'll be admitted to the hospital and will probably need to deliver.
If you're diagnosed with severe preeclampsia, you'll definitely have to spend the rest of your pregnancy in the hospital. And you may be transferred to a hospital where a high-risk pregnancy specialist can care for you. You'll be given magnesium sulfate intravenously to prevent seizures, as well as medication to lower your blood pressure if it's extremely high.
If you're at 34 weeks or more you may be induced or, in certain situations, delivered by c-section. If you're at less than 34 weeks, 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 extremely closely.
You'll be induced or delivered by c-section at the first sign that the preeclampsia is getting worse (including if you have HELLP or eclampsia) or your baby is not thriving, regardless of where you are in your pregnancy.
If you develop preeclampsia during 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.
After delivery, you'll remain under close supervision for a few days to keep tabs on your blood pressure and to watch for signs of other complications. Many cases of eclampsia and HELLP syndrome happen after delivery, usually within the first 48 hours. So your caregivers will continue to closely monitor your blood pressure.
Most women, particularly those with mild preeclampsia, see their blood pressure start to go down in a day or so. In more severe cases, it can remain elevated for longer.
Women whose blood pressure remains high are given magnesium sulfate intravenously for at least 24 hours after delivery to help prevent seizures. They may end up going home on blood pressure medication.
Is there any way I can avoid getting preeclampsia?
No one knows for sure how to prevent preeclampsia, although there's a lot of research going on in this area. A number of studies have looked into whether taking extra calcium or vitamins can help, but the results ultimately showed no benefit in most women.
The US Preventive Services Task Force now recommends that women at high risk for preeclampsia begin taking low dose aspirin after 12 weeks of pregnancy. Ask your care provider if you are considered high risk for preeclampsia and would be a candidate for aspririn therapy. Warning: Never take aspirin during pregnancy unless your caregiver recommends it.
Other than that, the best thing you can do is get good prenatal care and keep all your prenatal appointments. At each visit your healthcare provider will check your blood pressure and test your urine for protein. It's also important to be aware of the warning signs of preeclampsia so that you can alert your caregiver and get treated as soon as possible.
Is there a test that can predict my risk of getting preeclampsia?
Not yet. However, researchers have isolated some proteins produced by the placenta that are higher in the blood of women who go on to develop preeclampsia, and they're hopeful that a screening test may become available in the future.
If you're at risk for preeclampsia, your practitioner may have you come into the office for more frequent prenatal visits in your third trimester to increase the chance of detecting the condition early.
How is preeclampsia different from gestational hypertension?
If you develop high blood pressure after 20 weeks of pregnancy but don't have protein in your urine or other signs of preeclampsia, you're considered to have gestational hypertension. If protein is later found in your urine or blood test results are abnormal, your diagnosis changes to preeclampsia. This happens in about a quarter of the cases of women who are initially diagnosed with gestational hypertension.
Most likely, your blood pressure will return to a normal level after you have your baby. If your blood pressure is still high three months after you give birth, you'll be diagnosed with chronic hypertension.
If this is the case, it doesn't mean that gestational hypertension caused you to develop chronic hypertension. Instead, you probably had chronic hypertension all along and just didn't know it.
Pregnancy usually causes a woman's blood pressure to fall at the end of the first trimester and throughout much of the second trimester, so it can temporarily hide chronic hypertension. If your first prenatal visit wasn't until late in the first trimester or even later, your practitioner might not have noticed your high blood pressure until later in your pregnancy.
Where can I find more information?
Call the Preeclampsia Foundation at (800) 665-9341, or visit the foundation's website.