High Blood Pressure in Pregnancy What Is High Blood
Pressure? Blood pressure is the amount of force exerted by the blood
against the walls of the arteries. A person's blood pressure is considered high
when the readings are greater than 140 mm Hg systolic (the top number in the
blood pressure reading) or 90 mm Hg diastolic (the bottom number). In general,
high blood pressure, or hypertension, contributes to the development of
coronary heart disease, stroke, heart failure and kidney disease.
What Are the Effects of High Blood Pressure in
Pregnancy? Although many pregnant women with high blood pressure have
healthy babies without serious problems, high blood pressure can be dangerous
for both the mother and the fetus. Women with pre-existing, or chronic, high
blood pressure are more likely to have certain complications during pregnancy
than those with normal blood pressure. However, some women develop high blood
pressure while they are pregnant (often called gestational hypertension).
The effects of high blood pressure range from mild to severe. High blood
pressure can harm the mother's kidneys and other organs, and it can cause low
birth weight and early delivery. In the most serious cases, the mother develops
preeclampsia--or "toxemia of pregnancy"--which can threaten the lives of both
the mother and the fetus. What Is Preeclampsia?
Preeclampsia is a condition that typically starts after the 20th week of
pregnancy and is related to increased blood pressure and protein in the
mother's urine (as a result of kidney problems). Preeclampsia affects the
placenta, and it can affect the mother's kidney, liver, and brain. When
preeclampsia causes seizures, the condition is known as eclampsia--the second
leading cause of maternal death in the U.S. Preeclampsia is also a leading
cause of fetal complications, which include low birth weight, premature birth,
and stillbirth. There is no proven way to prevent preeclampsia. Most
women who develop signs of preeclampsia, however, are closely monitored to
lessen or avoid related problems. The only way to "cure" preeclampsia is to
deliver the baby. How Common Are High Blood Pressure and
Preeclampsia in Pregnancy? High blood pressure problems occur in 6
percent to 8 percent of all pregnancies in the U.S., about 70 percent of which
are first-time pregnancies. In 1998, more than 146,320 cases of preeclampsia
alone were diagnosed. Although the proportion of pregnancies with
gestational hypertension and eclampsia has remained about the same in the U.S.
over the past decade, the rate of preeclampsia has increased by nearly
one-third. This increase is due in part to a rise in the numbers of older
mothers and of multiple births, where preeclampsia occurs more frequently. For
example, in 1998 birth rates among women ages 30 to 44 and the number of births
to women ages 45 and older were at the highest levels in 3 decades, according
to the National Center for Health Statistics. Furthermore, between 1980 and
1998, rates of twin births increased about 50 percent overall and 1,000 percent
among women ages 45 to 49; rates of triplet and other higher-order multiple
births jumped more than 400 percent overall, and 1,000 percent among women in
their 40s. Who Is More Likely to Develop Preeclampsia?
- Women with chronic hypertension (high blood
pressure before becoming pregnant).
- Women who developed high blood pressure or
preeclampsia during a previous pregnancy, especially if these conditions
occurred early in the pregnancy.
- Women who are obese prior to pregnancy.
- Pregnant women under the age of 20 or over the age
of 40.
- Women who are pregnant with more than one baby.
- Women with diabetes, kidney disease, rheumatoid
arthritis, lupus, or scleroderma.
How Is Preeclampsia Detected?
Unfortunately, there is no single test to predict or diagnose preeclampsia. Key
signs are increased blood pressure and protein in the urine (proteinuria).
Other symptoms that seem to occur with preeclampsia include persistent
headaches, blurred vision or sensitivity to light, and abdominal pain.
All of these sensations can be caused by other disorders; they can also occur
in healthy pregnancies. Regular visits with your doctor help him or her to
track your blood pressure and level of protein in your urine, to order and
analyze blood tests that detect signs of preeclampsia, and to monitor fetal
development more closely. How Can Women with High Blood Pressure
Prevent Problems During Pregnancy? If you are thinking about having a
baby and you have high blood pressure, talk first to your doctor or nurse.
Taking steps to control your blood pressure before and during pregnancy--and
getting regular prenatal care--go a long way toward ensuring your well-being
and your baby's health. Before becoming pregnant:
- Be sure your blood pressure is under control.
Lifestyle changes such as limiting your salt intake, participating in regular
physical activity, and losing weight if you are overweight can be helpful.
- Discuss with your doctor how hypertension might
affect you and your baby during pregnancy, and what you can do to prevent or
lessen problems.
- If you take medicines for your blood pressure, ask
your doctor whether you should change the amount you take or stop taking them
during pregnancy. Experts currently recommend avoiding angiotensin-converting
enzyme (ACE) inhibitors and Angiotensin II (AII) receptor antagonists during
pregnancy; other blood pressure medications may be OK for you to use. Do not,
however, stop or change your medicines unless your doctor tells you to do
so.
While you are pregnant:
- Obtain regular prenatal medical care.
- Avoid alcohol and tobacco.
- Talk to your doctor about any over-the-counter
medications you are taking or are thinking about taking.
Does Hypertension or Preeclampsia During Pregnancy
Cause Long-Term Heart and Blood Vessel Problems? The effects of high
blood pressure during pregnancy vary depending on the disorder and other
factors. According to the National High Blood Pressure Education Program
(NHBPEP), preeclampsia does not in general increase a woman's risk for
developing chronic hypertension or other heart-related problems. The NHBPEP
also reports that in women with normal blood pressure who develop preeclampsia
after the 20th week of their first pregnancy, short-term
complications--including increased blood pressure--usually go away within about
6 weeks after delivery. Some women, however, may be more likely to
develop high blood pressure or other heart disease later in life. More research
is needed to determine the long-term health effects of hypertensive disorders
in pregnancy and to develop better methods for identifying, diagnosing, and
treating women at risk for these conditions. Even though high blood
pressure and related disorders during pregnancy can be serious, most women with
high blood pressure and those who develop preeclampsia have successful
pregnancies. Obtaining early and regular prenatal care is the most important
thing you can do for you and your baby. For More
Information The NHBPEP has updated clinical guidelines on high blood
pressure in pregnancy through a coordinating committee representing more than
45 medical organizations and agencies. NHBPEP is coordinated by the National
Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health.
The Working Group Report on High Blood Pressure in Pregnancy (NIH Publication
No. 00-3029) can be purchased through the NHLBI Health Information Network at
(301) 592-8573 and is available on the NHLBI Web site at: "http://www.nhlbi.nih.gov/health/prof/heart/hbp/hbp_preg.htm."
All women--and men--can take steps to prevent or manage
hypertension and other cardiovascular disorders. For more information, visit
the National Heart, Lung, and Blood Institute Web site at www.nhlbi.nih.gov, or
call the NHLBI Information Center at (301) 592-8573. |