High blood pressure and pregnancy

Hypertension (high blood pressure) is a common complication of pregnancy, occurring in as many as eight out of every 100 pregnancies.


Understanding blood pressure
Blood pressure is a measurement that reflects the amount of force blood exerts on the arteries (blood vessels that carry blood from the heart to the rest of the body) as it's pumped through the circulatory system by the heart. Adequate blood pressure is needed to provide blood flow to the major organs and other structures of the body. Two different measurements are taken to determine blood pressure. The first, or top, number (systolic blood pressure) measures the pressure on the artery walls when the heart contracts and forces blood through the body. The second, or bottom, number (diastolic blood pressure) measures the pressure on the artery walls when the heart is resting between contractions. An example of a reading would be 120/60 millimeters of mercury (mm Hg).
Hypertension develops when there is increased resistance to blood flow within the arteries. This resistance requires the heart to work harder to pump the blood. It can also damage the arteries and organs they feed. Technically, hypertension in pregnancy is defined as a sustained blood pressure of 140/90 mm Hg or higher.


Causes/associated factors
Some women have high blood pressure before they become pregnant, and others develop high blood pressure for the first time during pregnancy. The effects of high blood pressure during pregnancy can range from mild to severe. Symptoms and treatments vary depending on the type of high blood pressure.
Types of high blood pressure during pregnancy

Chronic hypertension is elevated blood pressure that was present before pregnancy or diagnosed before 20 weeks gestation and continues after the baby is born. Chronic hypertension increases the risk of poor fetal growth and preeclampsia. In fact, about 20 percent of women who have chronic hypertension develop preeclampsia at the same time, putting them at higher risk of serious complications.

Preeclampsia, or toxemia, is a serious condition that develops usually during the third trimester of pregnancy and disappears once the baby is born. In addition to elevated blood pressure, protein is present in the urine of women who have preeclampsia. The exact cause of preeclampsia is unknown. As research continues, we do know that certain changes in a woman's body lead to a narrowing of the blood vessels, accompanied by damage to certain vessels. In turn, these factors can lead to higher blood pressure, the delivery of less oxygen to many organs, seepage of fluid from the blood vessels into the surrounding tissues, and changes in how well the blood clots.

Risk factors for developing preeclampsia may include:

having your first baby ever or your first baby with a different father
being younger than age 20 or older than 35
having five or more pregnancies
carrying twins, triplets or other multiples
having chronic hypertension
having certain pre-existing illnesses, including diabetes, blood vessel disease, kidney disease or immune disorders (such as rheumatoid arthritis, lupus or scleroderma)
having a personal or family history of preeclampsia or eclampsia
being overweight
being African American
having excessive amniotic fluid
Preeclampsia can lead to serious complications for the mother or baby. When preeclampsia becomes severe, the effects on the brain can lead to seizures. The disease is then known as eclampsia. Another serious complication of preeclampsia is the HELLP syndrome. The early diagnosis and treatment of preeclampsia has significantly lowered the incidence of serious complications and fatalities. Women who have chronic hypertension and then develop preeclampsia are at a higher risk of serious complications. In addition, the presence of high blood pressure before pregnancy may make the diagnosis of preeclampsia more difficult. Most women who develop preeclampsia do not have a higher risk of developing chronic hypertension later in life. However, this risk increases if preecalampsia develops early in pregnancy, develops in more than one pregnancy or develops for the first time in a woman who has already had a pregnancy without preeclampsia.

Gestational hypertension is high blood pressure that develops after midpregnancy in a woman whose blood pressure was previously normal. It is not accompanied by protein in the urine, as is preeclampsia. If the woman's blood pressure returns to normal within 12 weeks after the baby is born, the condition is diagnosed as transient hypertension of pregnancy. If the blood pressure remains elevated, however, the condition is diagnosed as chronic hypertension. Women who have gestational hypertension can develop preeclampsia as the pregnancy progresses.


Signs/symptoms
Chronic hypertension and gestational hypertension may only be noted by an elevated blood pressure reading. If the blood pressure elevation is severe, chronic hypertension may be accompanied by other symptoms, such as headaches. Gestational hypertension may be accompanied by symptoms such as headaches, epigastric pain (pain near the pit of the stomach) and fewer platelets (blood cells that aid clotting).
Preeclampsia affects the heart, kidneys, liver, eyes, brain and placenta, all of which may lead to a variety of symptoms. The earliest signs of preeclampsia -- increased blood pressure, protein in the urine and excessive weight gain (5 pounds or more in one week) -- may go unnoticed at home. At each prenatal visit, however, these elements are evaluated for significant changes that could indicate the beginning of preeclampsia.

Preeclampsia may cause puffiness in your fingers and face. You may have swelling in your feet and ankles that is still present in the morning. (Normal swelling, experienced by many pregnant women during the later part of pregnancy, is usually mild and limited to the ankles and legs. It may be aggravated by warm weather and prolonged standing or sitting. It's often worse in the evening and much improved or even gone after a night in bed.) Of course, it's important to discuss any type of swelling with your doctor.

If preeclampsia progresses, more serious effects on other organs may become noticeable, including:

abdominal pain that's often in the upper right or upper mid abdomen
vomiting
constant headache that may be unrelieved by home care measures
visual changes, such as dimming, blurring, spots, flashing lights or, more rarely, blindness
extreme swelling of the face and hands (for example, eyes swollen shut or rings that won't come off)
swelling accompanied by feeling breathless
decreased amount of urine
liver enlargement
If eclampsia develops, it begins with a generalized seizure (convulsion). Most women have symptoms of preeclampsia first, but the condition can develop suddenly in some women who have no symptoms and only mild blood pressure elevation. Eclampsia can progress from seizures to coma.

A deceptive variation of preeclampsia is the HELLP syndrome, named for the following symptoms:

H: hemolysis, the destruction of red blood cells, which carry oxygen
EL: elevated liver enzymes due to liver damage
LP: low platelets, which prevents the blood from clotting normally

HELLP syndrome is deceptive because there may be only a minimal blood pressure elevation -- 10 to 20 percent of women have no increase at all. The prominent symptoms are often upper right abdominal pain, nausea and vomiting, which are sometimes diagnosed as other problems.


Diagnosis
Your doctor will check your weight, blood pressure and urine at each prenatal visit. If you have an abnormal increase in weight, your blood pressure is elevated or protein is found in your urine, specific blood tests can help the doctor confirm the diagnosis.

Treatment
Treatment of high blood pressure in pregnancy is necessary to avoid serious problems for both you and your baby.
Chronic hypertension
If you have chronic hypertension, you'll be closely monitored during your pregnancy. You may need regular blood and urine tests, as well as routine checks of your blood pressure and weight. You may need to see your doctor every two weeks until 28 weeks gestation, and then every week until delivery. Depending on your blood pressure, treatment may include activity and exercise restrictions, frequent rest periods during the day and restricted salt intake. Your doctor may prescribe medication to lower your blood pressure, as well as regular nonstress tests (one to two times a week) to monitor your baby's well-being. The nonstress test evaluates fetal heart rate accelerations (usually in association with fetal movement).

An early delivery (by 38 to 39 weeks or sometimes earlier) is usually planned for women who have chronic hypertension. If your blood pressure increases or you develop any signs of preeclampsia, you will be hospitalized and an even earlier delivery may become necessary.

If an early delivery is being considered, it's important to determine the age of the fetus. This can be done with an ultrasound (using sound waves to create an image of the fetus). An amniocentesis may be done to determine if the fetus's lungs are mature enough for delivery. During amniocentesis, the doctor withdraws a small amount of amniotic fluid (the fluid that surrounds and protects the fetus in the womb) for examination through a needle inserted into your abdomen.

Preeclampsia
If you're close to your due date when you develop preeclampsia and your baby is mature enough to live outside the womb, your doctor may recommend an early delivery to avoid serious complications. Labor may be induced or, in some cases, a cesarean section may be planned.

If you have mild preeclampsia and are not close to your due date, it may be possible to be treated at home in conjunction with more frequent office visits (usually twice a week). You may be restricted to bedrest, lying on your side for much of the time. It's also important to eat a balanced diet with adequate protein and calories. Your doctor may ask you to keep track of your baby's movements (known as a "kick count") every day. You may need regular blood and urine tests, as well as routine checks of your blood pressure and weight. Regular nonstress tests (one to two times a week) will be done to monitor your baby's well-being. If your symptoms are more severe or you're unable to get sufficient rest at home, you may need to be hospitalized until the baby is born.

For severe preeclampsia, prompt delivery of the baby is best. Depending on the situation, labor may be induced or you may need a cesarean section. This may pose problems, however, if you're far from your due date. If there is time, corticosteroid medication will be given to help the baby's lungs mature more rapidly. Other medication to lower your blood pressure and prevent seizures may also be given.

The symptoms of preeclampsia typically resolve soon after delivery, even if the preeclampsia was severe. You may need medication to prevent seizures for at least 24 hours after the delivery, however. If your baby was delivered early, he or she will receive specialized care in a neonatal intensive care unit.

Gestational hypertension
If you have gestational hypertension, you will be monitored closely for signs of preeclampsia. Your treatment will depend on the progression of your blood pressure and other symptoms that may develop.


Complications
Mild to moderate hypertension usually poses no serious complications, but preeclampsia or chronic hypertension that leads to preeclampsia can be life-threatening for both you and your baby.
Serious chronic hypertension can lead to preeclampsia or abruptio placenta (when the placenta detaches from the uterus before the baby is born).

Complications of preeclampsia include:

bleeding into the brain
liver, kidney or heart failure
eclampsia
HELLP syndrome
abruptio placenta
poor growth of the fetus in the womb
premature birth
In some cases, the baby may not survive. In these situations, it's important for you and your partner to talk about your feelings with someone who understands and can provide the support you need. This could be your doctor, a counselor or someone who has experienced a similar loss. Remember, grief following the loss of a baby is normal and expected.


Prevention
It may not be possible to prevent high blood pressure from developing during pregnancy, but prompt diagnosis and treatment can limit or prevent complications. Seeking prenatal care early in pregnancy and continuing it throughout your pregnancy is vital. If you have preeclampsia risk factors, your doctor will probably want to see you more often during pregnancy.
If you have chronic high blood pressure, remember the importance of preconception planning. Discuss pregnancy with your doctor and take any necessary steps to ensure proper control of your blood pressure. This may include maintaining a normal weight, getting regular exercise, reducing stress, and taking medication as recommended. Your health care provider may prescribe an alternate blood pressure medication that's safer during pregnancy. Once you become pregnant, it's essential to see your doctor as often as recommended throughout your pregnancy.