Pregnancy and Hypertension

Hypertension, or high blood pressure, can cause serious complications for both the fetus and the mother. Some pregnant women are chronic hypertension sufferers, meaning they have the condition before they become pregnant. Others develop gestational hypertension during pregnancy. Still others develop a hypertensive disorder called preeclampsia.

Hypertensive disorders are the number two cause of maternal deaths in the United States, accounting for nearly 15 percent of such deaths.

Preeclampsia

Preeclampsia is the most common high blood pressure disorder of pregnancy. It occurs in 5 to 8 percent of pregnant women each year and can cause the most serious problems for mother and baby. Preeclampia is diagnosed when a woman with no history of high blood pressure develops hypertension (blood pressure of more than 140/90 mmHg) about halfway through her pregnancy and secretes protein in her urine. No one knows what causes this condition, and the only definitive treatment is delivering the child. In the meantime, preeclampsia wreaks havoc on the mother's vascular system, dilating (enlarging) some blood vessels, constricting others and forcing fluid out into the surrounding tissues. This, in turn, affects the placenta, kidney, liver, brain and fetus. Preeclampsia can develop gradually or appear suddenly, and it can range from mild to severe. In its most severe form, preeclampsia can lead to eclampsia (maternal seizures), stroke or a bleeding liver, all of which can cause the mother's death. There is also great risk to the unborn child, which may face severe growth restriction and an increased risk of stillbirth.

Chronic Hypertension

Another hypertensive disorder of pregnancy is chronic hypertension. Women who have chronic hypertension before pregnancy will continue to have this condition during pregnancy. Women with chronic hypertension are at higher risk for developing preeclampsia, called, in this case, superimposed preeclampsia. In fact, nearly one in four women with chronic hypertension will develop superimposed preeclampsia during pregnancy, usually at mid-term. In such cases, the prognosis for both mother and child is worse than it is for women who develop high blood pressure during their pregnancy. Pregnant women with chronic hypertension are at higher risk for premature birth, restricted growth or death of the fetus, congestive heart failure and renal failure.

In 2006, an article in the New England Journal of Medicine discussed the relationship between angiotensin-converting enzyme (ACE) inhibitors, medications used to control blood pressure, and the occurrence of congenital birth defects. Researchers determined that women taking ACE inhibitors were about three times as likely to deliver a baby with congenital defects as women who were taking some other type of medication for high blood pressure. The birth defects were mainly in the central nervous system and the heart. Potential damage to the fetus' kidneys had been previously noted; because of this, ACE inhibitors are not recommended in the second and third trimesters. If you are taking an ACE inhibitor for hypertension and are planning to become pregnant or are currently pregnant, discuss this latest research with your health care provider. Do not stop taking your medication without first talking to your provider.

Gestational Hypertension

A third hypertensive disorder of pregnancy is gestational hypertension. This develops about halfway through a pregnancy, but differs from preeclampsia in that no protein is present in the urine. This type of hypertension usually goes away after pregnancy. If it does not, the diagnosis is changed to chronic hypertension.

Health care providers checking for preeclampsia in pregnant women without chronic high blood pressure will look for elevated blood pressure levels and protein in the urine. In women with chronic high blood pressure, signs of possible preeclampsia include the new appearance or an increase of protein in the urine. Another sign: a sudden increase in blood pressure if the blood pressure previously was well controlled.

Doctors usually admit women with mild cases of preeclampsia to a hospital for observation. If the mother and baby are stable and delivery is not imminent, such women may be sent home and put on bed rest. They may undergo frequent lab tests, home blood pressure monitoring and fetal heart rate monitoring or sonograms. Women with severe cases of preeclampsia are hospitalized. If their delivery date is not imminent, they receive steroids to help the baby's lungs mature. Delivery is delayed until severe headaches, uncontrollable hypertension, poor fetal status or abnormal liver lab results indicate the baby should be delivered. If a mother with a severe case of preeclampsia is at or near term, the baby is delivered.

Fortunately, for women with gestational hypertension, the high blood pressure and signs of organ dysfunction associated with preeclampsia typically disappear within six weeks of delivery. But women with early-onset preeclampsia or preeclampsia in more than one pregnancy are more likely to develop hypertension later in life.

What to Do

You should have your blood pressure checked regularly if you become pregnant. You should also talk with your doctor about lifestyle changes, such as increasing your physical activity levels and controlling your weight.

Use Medicine Effectively

Many women with chronic hypertension can control their blood pressure without medications, or with less medication than they were using before they became pregnant. Most hypertension medications, however, can be safely used during pregnancy. There are two exceptions: the ACE inhibitor and angiotensin II receptor agonist classes of medications should be discontinued. These medications might cause central nervous system, heart and fetal kidney abnormalities.

Self-care Steps for Pregnancy and Hypertension

• Exercise and maintain what your doctor tells you is a proper weight.

• If your doctor suggests it, get a home blood pressure cuff, take your blood pressure regularly and report any high readings.