Home > Health Library > High Blood Pressure During Pregnancy
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.
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.
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.
Experts don't know the exact cause of high blood pressure during pregnancy.
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.
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.
Your doctor may have you take medicine if he or she thinks your blood pressure is too high.
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.
Learning about high blood pressure during pregnancy:
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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 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.
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.
High blood pressure is typically found during regular
Certain tests are given at
each prenatal visit to check for high blood pressure. These
Other tests may also be used to monitor for signs of
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:
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.
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:
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.
If you have high blood pressure during pregnancy, take
steps to help control your blood pressure:
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):
November 5, 2012
Sarah Marshall, MD - Family Medicine & William Gilbert, MD - Maternal and Fetal Medicine
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