High Blood Pressure


The information provided below is for readers based in the United States of America. Readers outside of the United States of America should seek the information from local sources.

What is high blood pressure?

During pregnancy, you are considered to have high blood pressure (hypertension), if the systolic pressure (blood pressure when the hearts ventricles contract) is more than 140 mm Hg, or if the diastolic pressure (pressure when the ventricles relax) is more than 90 mm Hg. Outside of pregnancy, people are considered to have early high blood pressure, for which medication should be considered if systolic pressure is in the 130s. During pregnancy, however, pressure in this moderate range is only monitored to see if it gets higher and doctors would not try to lower it with medication as this could reduce blood flow to the uterus and placenta.

Hypertension in pregnancy can be pre-existing, or chronic, meaning that its a continuation of hypertension that you had before getting pregnant. Hypertension also is a prominent feature of specific syndromes that can develop as a complication of pregnancy. One such syndrome is called preeclampsia and the other is called HELLP. In either of these syndromes, hypertension can occur as a new-onset condition, meaning that blood pressure was normal prior to pregnancy, or prior to 20 weeks gestation (about the midpoint of pregnancy), or the preeclampsia or HELLP syndrome can be superimposed on pre-existing hypertension. Hypertension is defined as severe if the systolic pressure climbs higher than 160 mm Hg, or the diastolic pressure climbs higher than 110 mmHg.

How common is high blood pressure during pregnancy?

In the United States, approximately 7 percent of young adults have high blood pressure. Up to middle age, systolic pressure is generally higher in men than women, but many women nevertheless are hypertensive and at risk of blood pressure increases during pregnancy, because of the possibility of the hypertension pregnancy syndromes. Smoking, obesity, and kidney disease all increase the risk of developing hypertension.

How is high blood pressure diagnosed?

Hypertension is diagnosed using a sphygmomanometer (a blood pressure cuff machine) to measure your blood pressure, which must be high on at least two readings.

Does high blood pressure cause problems during pregnancy?

High blood pressure can cause headache, dizziness, and nose bleeding, placental abruption (detachment of the placenta from the uterine wall) leading to severe bleeding, myocardial infarction (heart attack), heart failure, rupture of arteries, strokes, and atrial fibrillation (quivering of the hearts upper chambers). Over the long-term, hypertension can cause damage to multiple organs, including the heart, kidneys, and eyes.

Does high blood pressure during pregnancy cause problems for the baby?

Along with placental abruption, which can kill the developing baby, hypertension can lead to intrauterine growth restriction (slow growth of the baby in the womb), and low birth weight.

What to consider about taking medications when you are pregnant:

  • The risks to yourself and your baby if you do not treat the hypertension
  • The risks and benefits of each medication you use when you are pregnant
  • The risks and benefits of each medication you use when you are breastfeeding

What should I know about using medication to treat my high blood pressure during pregnancy?

Medications for women with high blood pressure consist of a variety of blood-pressure lowering drugs. These include labetalol, hydralazine, nifedipine, and sodium nitroprusside, which are used for emergency control of blood pressure. Labetalol (an example of a group of drugs called beta-blockers) and nifedipine also are used for long-term control of blood pressure, as are a drug called methyldopa and a group of drugs called calcium channel blockers. These drugs all have side effects and benefits that must be balanced, but if your blood pressure is very high, or if you have preeclampsia, the benefits are considered to outweigh the risks, including the risks for the developing baby.

In cases of preeclampsia, or eclampsia (a complication of preeclampsia in which seizures develop), an agent called magnesium sulfate is given to prevent or stop seizures.

Groups of blood pressure-lowering drugs that should be avoided during pregnancy as they can cause birth defects include ACE inhibitors and angiotensin receptor blockers. If you are taking a drug from either of these categories prior to pregnancy, you should see your doctor to discuss changing to a different medication for pregnancy.

Who should NOT stop taking medication for high blood pressure during pregnancy?

Everyone who needs blood pressure-lowering medication prior to pregnancy should continue taking it. However, if you are taking certain types of medication, such as an ACE inhibitor or an angiotensin receptor blocker, you should consider having your doctor change the medication.

What should I know about choosing a medication for my high blood pressure during pregnancy?

You may find Pregistrys expert reports about the individual medications to treat high blood pressure here. Additional information can also be found in the sources listed at the end of this report.

What should I know about taking a medication for my high blood pressure when I am breastfeeding?

Methyldopa, labetalol and other beta-blockers (propranolol, atenolol, metoprolol), calcium-channel blockers, nifedipine, and hydralazine are all safe to use while breastfeeding.

What alternative therapies besides medications can I use to treat my high blood pressure during pregnancy?

There are no alternatives to medications once your systolic pressure is above 140 mm HG or your diastolic pressure is above 90 mm Hg. However, lifestyle modifications (nutritional changes, exercise, and weight reduction) are viable treatments for people who have early hypertension with systolic pressure in the range of 120 -140 and diastolic in the range of 80 90 mm Hg. Some patients with hypertension are asked to restrict salt in their diet, for example.  Some people also benefit from taking a class in stress reduction, mindfulness, or meditation.

What can I do for myself and my baby when I have high blood pressure during pregnancy?

Comply with the treatment plan prescribed by your doctor, including taking all needed medications on the appropriate schedule.

Resources for high blood pressure in pregnancy:

For more information about high blood pressure during and after pregnancy, contact http://www.womenshealth.gov/ (800-994-9662 [TDD: 888-220-5446]) or read the following articles:


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General information

It is very common for women to worry about having a miscarriage or giving birth to a child with a birth defect while they are pregnant. Many decisions that women make about their health during pregnancy are made with these concerns in mind.

For many women these concerns are very real. As many as 1 in 5 pregnancies end in a miscarriage, and 1 in 33 babies are born with a birth defect. These rates are considered the background population risk, which means they do not take into consideration anything about the health of the mom, the medications she is taking, or the family history of the mom or the baby’s dad. A number of different things can increase these risks, including taking certain medications during pregnancy.

It is known that most medications, including over-the-counter medications, taken during pregnancy do get passed on to the baby. Fortunately, most medicines are not harmful to the baby and can be safely taken during pregnancy. But there are some that are known to be harmful to a baby’s normal development and growth, especially when they are taken during certain times of the pregnancy. Because of this, it is important to talk with your doctor or midwife about any medications you are taking, ideally before you even try to get pregnant.

If a doctor other than the one caring for your pregnancy recommends that you start a new medicine while you are pregnant, it is important that you let them know you are pregnant.

If you do need to take a new medication while pregnant, it is important to discuss the possible risks the medicine may pose on your pregnancy with your doctor or midwife. They can help you understand the benefits and the risks of taking the medicine.

Ultimately, the decision to start, stop, or change medications during pregnancy is up to you to make, along with input from your doctor or midwife. If you do take medications during pregnancy, be sure to keep track of all the medications you are taking.

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