Hypertension in Pregnancy Health Article

Hypertension (high blood pressure) is a common medical disorder, affecting 20 to 30 percent of American adults. It tends to be a "hidden" or "silent" problem that usually does not cause obvious symptoms but can eventually lead to heart disease, heart attack, and other potentially fatal illnesses.

Modern health care has decreased the number and severity of complications due to high blood pressure; in fact, mild hypertension during pregnancy does not cause adverse effects for most women or their babies. Nevertheless, hypertension does complicate as many as 7 to 10 percent of pregnancies and is still one of the leading causes of death among expectant mothers. Severe hypertension increases a mother's risk of heart attack, heart failure, stroke, and kidney failure. When a pregnant mother's blood pressure is severely elevated, oxygen and nutrients cannot pass as easily through the placenta and to the baby. As a result, fetal growth restriction, premature birth, and placental abruption (separation of the placenta from the uterus) may occur.

Prenatal care is important for all pregnant women. If you are pregnant and have hypertension, early prenatal care is invaluable. You and your doctor will discuss many issues during your pregnancy, including the use of anti-hypertensive medications and the possible need to deliver your baby prematurely.

What Is Blood Pressure?

Blood pressure is the force exerted against the blood vessel walls. This force is predominantly the result of the volume of blood pumped with each heartbeat and the elasticity (flexibility) of the blood vessel walls. It is measured in millimeters of mercury (mmHg) above atmospheric pressure and consists of two numbers-such as 140/90 mmHg.

• The top number of a blood pressure reading is called the systolic blood pressure and represents the maximum pressure against a blood vessel when the heart is beating.
• The diastolic blood pressure, the bottom number, represents the pressure against a blood vessel when the heart is at rest (between beats).

Blood pressure varies with age, gender, health and fitness level, weight, and other variables. In many people, blood vessels become less elastic ("harder" or "narrower") over time, causing a rise in blood pressure. Adults with a systolic blood pressure consistently above 140 mmHg and/or a diastolic blood pressure above 90 mmHg are diagnosed with hypertension.

About 90 percent of adults with high blood pressure are diagnosed with essential hypertension - that is, the disorder is hereditary and not due to an underlying medical cause. Less than 10 percent of high blood pressure cases are secondary - that is, due to specific causes, such as diabetes or kidney disease. Obesity, lack of exercise, smoking, use of certain medications, a high-salt diet, and other factors can cause or contribute to hypertension. Modifying these risk factors can lower a person's blood pressure.

Hypertension During Pregnancy

Hypertension during pregnancy is defined according to a spectrum. (See Table 1 below for more information.)

• At one end of the spectrum are women who had high blood pressure before pregnancy or were diagnosed with high blood pressure during the first half of pregnancy. High blood pressure usually persists after delivery (chronic hypertension), has no underlying medical cause, and is often diagnosed as essential.
• At the other end of the spectrum are women who have no history of hypertension but who develop high blood pressure during pregnancy. During pregnancy, these women may develop proteinuria (protein in the urine) or edema (excessive swelling), symptoms indicative of preeclampsia or eclampsia.
• Between these two ends of the spectrum are women who have chronic hypertension. During pregnancy, this condition may be superimposed with varying degrees of preeclampsia or eclampsia.

Women who have hypertension during pregnancy (chronic or pregnancy-related) may develop proteinuria and/or edema late in their pregnancy. This condition is known as preeclampsia. Some women develop eclampsia (preeclampsia complicated by convulsions or seizures). Both are high-risk conditions for the mother and her baby.

Table 1 highlights the classifications of hypertension during pregnancy. It is important for your doctor to accurately classify your disorder, since it helps her treat you and your baby.

Mild or moderate high blood pressure usually remains stable during pregnancy and has little effect on you or your baby. Of course, a risk remains that pregnancy will exacerbate your high blood pressure, increasing the possibility of complications for you and your baby. Severe hypertension of any cause increases the risk to mother and baby, but the women at highest risk are those with preeclampsia or eclampsia.

In this section, you learn about a number of hypertensive disorders that can occur during pregnancy-including gestational hypertension, preeclampsia and its variations, and eclampsia-and how pre-existing hypertension can affect your pregnancy. You can read about how these conditions are detected, what complications they can cause, and how they are managed.

For more information, go to:

• Hypertension in Pregnancy: Gestational Hypertension
• Hypertension in Pregnancy: Preclampsia
• Hypertension in Pregnancy: Eclampsia
• Hypertension in Pregnancy: Chronic Hypertension
• Hypertension & Preeclampsia