High Blood Pressure During Pregnancy

Topic Overview

Is this topic for you?

This topic is about high blood pressure that some women get during pregnancy. For information about preeclampsia, a more serious kind of high blood pressure, see the topic Preeclampsia.

What is high blood pressure?

Blood pressure is a measure of how hard your blood pushes against the walls of your arteries. If the force is too hard, you have high blood pressure (also called hypertension).

Blood pressure is shown as two numbers. The top number (systolic) is the pressure when the heart pumps blood. The bottom number (diastolic) is the pressure when the heart relaxes and fills with blood.

Blood pressure is high if the top number is more than 140 or if the bottom number is more than 90.

Blood pressure during pregnancy

Normally, a woman's blood pressure drops during her second trimester. Then it returns to normal by the end of the pregnancy.

But in some women, blood pressure goes up very high in the second or third trimester. This is sometimes called gestational hypertension, and it can lead to preeclampsia. You will need to have your blood pressure checked often and you may need treatment. Usually, the problem goes away after the baby is born.

Some women have chronic high blood pressure before they get pregnant. High blood pressure that started before pregnancy usually doesn't go away after the baby is born.

A small rise in blood pressure may not be a problem. But your doctor will watch your pressure to make sure it doesn't get too high. The doctor also will check you for preeclampsia.

Very high blood pressure keeps your baby from getting enough blood and oxygen. This could limit your baby's growth or cause the placenta to pull away too soon from the uterus. High blood pressure also could lead to stillbirth.

What causes high blood pressure during pregnancy?

Experts don't know the exact cause of high blood pressure during pregnancy.

What are the symptoms?

High blood pressure usually doesn't cause symptoms. But very high blood pressure sometimes causes headaches and shortness of breath or changes in vision.

If you have high blood pressure, tell your doctor right away if you get a headache or belly pain. These are early signs of preeclampsia.

How is high blood pressure diagnosed?

High blood pressure is usually found during a prenatal visit.

This is one reason why it's so important to go to all of your prenatal visits. You need to have your blood pressure checked often. During these visits, your blood pressure is measured. A sudden increase in blood pressure often is the first sign of a problem.

How is it treated?

Your doctor may have you take medicine if he or she thinks your blood pressure is too high.

Does high blood pressure during pregnancy lead to long-term high blood pressure?

If you have high blood pressure during pregnancy but had normal blood pressure before pregnancy, your pressure is likely to go back to normal after you have the baby.

Frequently Asked Questions

Learning about high blood pressure during pregnancy:

Being diagnosed:

Getting treatment:

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  High Blood Pressure: Checking Your Blood Pressure at Home

Symptoms

If you get high blood pressure during pregnancy, you will probably not have any symptoms. It usually requires a blood pressure check to detect high blood pressure.

Blood pressure is shown as two numbers. The top number (systolic) is the pressure when the heart pumps blood. The bottom number (diastolic) is the pressure when the heart relaxes and fills with blood.

Blood pressure is too high if the top number is more than 140, or if the bottom number is more than 90 (usually described as "140 over 90" or 140/90). Blood pressure measured at 140/90 or higher is classified as high and 160/110 or higher is classified as severe.

Chronic high blood pressure

Some women have high blood pressure during pregnancy because they had chronic high blood pressure before getting pregnant.

Women with chronic high blood pressure who become pregnant normally have a drop in blood pressure during the first two trimesters. But during the late second or in the third trimester, blood pressure returns to higher-than-normal levels. After delivery, their blood pressure remains high.

If you aren't certain that you had normal blood pressure before pregnancy, it is possible that you had chronic high blood pressure before you got pregnant. If so, your blood pressure may remain high after your pregnancy.

High blood pressure that develops before the 20th week of pregnancy is usually a sign of either chronic high blood pressure or short-term, mild high blood pressure. In rare cases, it is an early sign of preeclampsia.

Exams and Tests

High blood pressure is typically found during regular prenatal checkups.

Routine prenatal tests

Certain tests are given at each prenatal visit to check for high blood pressure. These include:

  • Blood pressure readings. Blood pressure is always monitored closely during pregnancy.
  • Urine tests to check for too much protein in the urine. This is a sign of kidney damage caused by preeclampsia.
  • Weight measurement. Rapid weight gain can be a sign of preeclampsia.

Tests for women considered high-risk for preeclampsia

Other tests may also be used to monitor for signs of preeclampsia, including:

  • Blood tests to check for problems such as HELLP syndrome and kidney damage.
  • Creatinine clearance test, which requires both a blood sample and a 24-hour urine collection, to check kidney function.
  • 24-hour urine collection test to look for protein in the urine.

Tests for the baby

If you get high blood pressure while you're pregnant, the baby's health also will be closely monitored. The more severe your condition, the more often you'll need testing, ranging from once a week to daily.

Tests commonly used include:

  • Electronic fetal heart monitoring (including nonstress tests), which records the baby's heart rate.
  • Fetal ultrasound, which uses reflected sound waves to produce a computerized picture of the baby, placenta, and uterus to check:
    • The baby's well-being and growth.
    • The condition of the placenta and the possibility of placenta abruptio.
    • The amount of amniotic fluid surrounding the baby.
  • Doppler ultrasound to check how well the placenta is working.

Treatment Overview

If you have high blood pressure during your pregnancy, your treatment may include close monitoring by your doctor and taking blood pressure medicine.

Your doctor may have you take medicine if he or she thinks your blood pressure is too high. Some women with ongoing high blood pressure stay on blood pressure medicine but take a lower dose during pregnancy if their blood pressure improves.

Blood pressure medicines

Medicines used to control chronic high blood pressure during pregnancy include:

Some high blood pressure medicines are dangerous during pregnancy.1 If you take high blood pressure medicines, talk to your doctor about the safety of your medicine before you become pregnant or as soon as you learn you are pregnant. Make sure that your doctor has a complete list of all medicines that you are taking.

Other blood pressure medicines that may be used include:

  • Hydralazine, an intravenous medicine for quickly lowering severely high blood pressure during pregnancy.
  • Labetalol, an intravenous medicine for quickly lowering severely high blood pressure in the hospital, and also an oral medicine for controlling high blood pressure during pregnancy.

Lowering blood pressure too much or too fast can reduce blood flow to the placenta, causing problems for the baby. So medicine is reserved for preventing severely high blood pressure levels that may be life-threatening to you or the baby.

Home Treatment

If you have high blood pressure during pregnancy, take steps to help control your blood pressure:

  • Go to all of your prenatal checkups. It is important to monitor your blood pressure, because a dangerous increase in blood pressure can occur without symptoms. You may also want to keep track of your blood pressure readings at home.
  • If you smoke, quit smoking. This helps decrease your blood pressure and improve your baby's growth and health.
  • Don't gain too much weight during your pregnancy. Talk to your doctor about how much is healthy for you to gain.
  • Get regular mild exercise during pregnancy. Walking or swimming several times weekly can be healthy for you and your developing baby.
  • Reduce stress. Find time to relax, especially if you continue to work, are parenting small children at home, or have a hectic schedule.

Other Places To Get Help

Organization

American Congress of Obstetricians and Gynecologists (ACOG)
Web Address: www.acog.org

References

Citations

  1. Cooper WO, et al. (2006). Major congenital malformations after first-trimester exposure to ACE inhibitors. New England Journal of Medicine, 354(23): 2443–2451.

Other Works Consulted

  • American College of Obstetricians and Gynecologists (2012). Chronic hypertension in pregnancy. ACOG Practice Bulletin No. 125. Obstetrics and Gynecology, 119(2): 396–407.
  • American College of Obstetricians and Gynecologists (2002, reaffirmed 2010). Diagnosis and management of preeclampsia and eclampsia. ACOG Practice Bulletin No. 33. Obstetrics and Gynecology, 99(1): 159–167.

Credits

By Healthwise Staff
Sarah Marshall, MD - Family Medicine
William Gilbert, MD - Maternal and Fetal Medicine
Last Revised November 5, 2012

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