High blood pressure at 15 weeks pregnant

FAQ034
Last updated: April 2022
Last reviewed: April 2022

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This information is designed as an educational aid for the public. It offers current information and opinions related to women's health. It is not intended as a statement of the standard of care. It does not explain all of the proper treatments or methods of care. It is not a substitute for the advice of a physician. Read ACOG’s complete disclaimer.

High blood pressure in pregnancy (hypertension) can cause serious problems for you and your baby, so your provider will check for it at every prenatal visit. There are often no symptoms of high blood pressure in pregnancy, so you may not be aware of it until your blood pressure is measured. Most women with high blood pressure can have a healthy pregnancy and manage the condition with lifestyle changes, medication, and close monitoring.

What is high blood pressure?

High blood pressure means that the force of the blood flowing through your blood vessels is too strong. A certain amount of pressure is necessary for blood to move around your body, but too much pressure – called hypertension – can cause serious problems for you and your baby during pregnancy. That's why your healthcare provider will check your blood pressure at every prenatal visit.

About 8 percent of women in the United States have some kind of hypertension during pregnancy. Some women have high blood pressure before getting pregnant, and some develop it during pregnancy. Preeclampsia, a dangerous blood pressure disorder, can happen during pregnancy or postpartum.

What is normal blood pressure in pregnancy?

Normal blood pressure in pregnancy is less than 120/80 mm Hg. That's expressed as "120 over 80."

Blood pressure is measured in millimeters of mercury (mmHg), and the measurement has two numbers. The top (systolic) number is the pressure of your blood against the walls of your arteries when your heart contracts and pumps blood. The bottom (diastolic) number is when the heart relaxes and fills with blood.

High blood pressure is diagnosed when either the systolic or diastolic number is at an unhealthy level – or if both are.

The guidelines for blood pressure readings during pregnancy are:

• Normal: Less than 120/80 mm Hg
• Mild hypertension: Higher than 140/90 mm Hg
• Severe hypertension: Higher than 160/110 mm Hg

These numbers are different than guidelines for blood pressure for people who aren't pregnant.

Your provider or a medical assistant will measure your blood pressure at each prenatal visit. Your healthcare provider may also ask you to monitor your blood pressure at home.

Before concluding that you have hypertension, your provider will probably take your blood pressure readings at least two different times. That's because your blood pressure varies throughout the day, and it can go down when you're relaxed and up when you're active or stressed. Some people may have an above-normal blood pressure reading because they get nervous at the doctor's office – a phenomenon called "white-coat hypertension."

If your blood pressure reading is elevated, your provider will take a reading again in 15 minutes. If it's still elevated, they'll decide what to do next, based on your current blood pressure, medical history, previous blood pressures, and gestational age.

If your reading is in the severe range, you'll be sent to the hospital for evaluation, where you'll receive IV meds, blood work, and fetal monitoring. If your reading is in the mild range, you may still need to be seen at the hospital for blood work and monitoring, or you may receive further testing in the office, oral medication, and directions to return to the office for monitoring.

Obstetricians and midwives take hypertension in pregnancy very seriously because of the possible serious complications for both mother and baby (see below), so be sure to follow your provider's directions.

Types of high blood pressure in pregnancy

There are three main types of high blood pressure that women experience in pregnancy:

Chronic hypertension is high blood pressure that existed before pregnancy or is diagnosed before 20 weeks. If you have a high blood pressure reading early in your pregnancy, it's likely you had hypertension before you became pregnant. (It's also called preexisting or pregestational hypertension.) Chronic hypertension is also the diagnosis for women who have high blood pressure for longer than 12 weeks after delivery.

Having chronic hypertension can put you at risk for preeclampsia later in pregnancy. About 1 in 4 women with chronic hypertension will develop preeclampsia.

A new study suggests that women with pre-pregnancy hypertension should be treated with blood pressure medication during their pregnancy to keep their blood pressure below 140/90. Previous conventional wisdom encouraged treatment only for those with readings above 160/110. Women who were treated more promptly in the study had fewer severe complications, and their babies grew just as well as those in the non-treatment group.

Gestational hypertension is high blood pressure that usually occurs for the first time at 20 weeks of pregnancy or later. It's diagnosed if you have new onset high blood pressure during pregnancy but not preeclampsia. Women with gestational hypertension usually have just a small increase in blood pressure, but 10 to 25 percent of women with the condition may show signs of preeclampsia later in pregnancy.

More than 6 percent of pregnant women in the United States develop gestational hypertension. It's temporary and almost always goes away after childbirth, but it does put some women at higher risk for developing chronic hypertension later in life.

Preeclampsia is a serious condition in which women develop high blood pressure after 20 weeks of pregnancy and have signs that certain organs aren't working properly. Your healthcare provider will check blood and urine tests for signs of preeclampsia (such as protein in your urine).

The rate of preeclampsia has risen 25 percent in the last two decades and now affects about 1 in every 25 pregnancies in the United States. This increase may be due to more women having babies at a later age, or because of higher rates of obesity, diabetes, and hypertension – all of which increase the risk of preeclampsia. If preeclampsia happens before 32 weeks of pregnancy, it's called early-onset preeclampsia. Preeclampsia can also happen postpartum.

If you've had preeclampsia, you're at increased risk for high blood pressure, kidney disease, heart attack, and stroke later in life. Your risk of preeclampsia in a future pregnancy is elevated, too.

If you already have chronic high blood pressure and develop preeclampsia, it's called superimposed preeclampsia.

Symptoms of high blood pressure in pregnancy

High blood pressure often doesn't cause any noticeable symptoms unless it's dangerously high. So you may not be aware of it unless your blood pressure is measured.

But high blood pressure can sometimes cause:

• Persistent headache
• Changes in vision – blurred or double vision

What causes high blood pressure during pregnancy?

It's not always clear what causes high blood pressure during pregnancy, but risk factors include:

• Age (the older you are, the higher the risk.)
• Having a personal or family history of gestational hypertension or preeclampsia
• Being African American
• Certain medical conditions before pregnancy, including diabetes, chronic hypertension, lupus, or chronic kidney disease.
• Having had preeclampsia in a previous pregnancy
• Being overweight (having a body mass index, or BMI, over 30)
• Being sedentary
• Smoking cigarettes
• Eating too much salt
• Drinking more than two alcoholic drinks a day
• Poor nutrition, especially a diet that lacks fruits and vegetables
• Carrying twins or higher multiples
• Having had assisted reproductive technology

Complications of high blood pressure during pregnancy

Most expecting moms with high blood pressure do just fine. If you have chronic hypertension, you and your caregiver will likely be able to manage it with lifestyle changes, medication, and close monitoring for complications.

Most women who get gestational hypertension have only a mild form of the condition and don't develop it until near the end of pregnancy. If you're in this category, you have a somewhat higher risk of having labor induced. But other than that, you and your baby are likely to do as well as you would if you had normal blood pressure.

But sometimes high blood pressure results in a decreased blood flow to your baby, which means they may not get enough nutrients and oxygen to grow properly. The more severe your high blood pressure and the earlier in pregnancy it appears, the greater your risk for problems. There's also a greater risk of complications if you've had high blood pressure for a long time and it has damaged your heart, kidneys, or other organs. The risks are also higher for women with high blood pressure that's caused by another medical condition, such as diabetes or kidney disease.

High blood pressure risks during pregnancy include:

• Having a baby who's smaller than normal: High blood pressure can restrict blood flow in the placenta, which mean that your baby doesn't get all the necessary nutrients and grows more slowly than usual (this is called intrauterine growth restriction or IUGR).
• C-section birth: Women with high blood pressure may be at a higher risk of delivering by cesarean section.
• Placental abruption: In this condition, part or all of the placenta separates from the uterine wall before the baby is born. There are different degrees of placental abruption, and in severe cases, a baby may not get enough oxygen and will need to be born right away.
• Preterm birth: If complications develop, or it looks like your baby isn't growing well, it may be necessary to deliver early. The more severe your high blood pressure is, the more likely you are to need an early delivery.

If your high blood pressure develops into preeclampsia, you're at risk of:

• Seizures (eclampsia)
• Stroke
• Future cardiovascular disease
• HELLP syndrome

How to prevent high blood pressure during pregnancy

Some risk factors can't be changed, such as your genes or having certain health conditions. But you can make changes to reduce other risk factors, and these are important to know about when you're trying to get pregnant.

Some steps you can take to reduce your high blood pressure risks:

• Maintain a healthy weight and diet. Talk to your provider about how much weight to gain during pregnancy. The DASH diet (which recommends plenty of fruits, vegetables, and whole grains and limits saturated fats, salt, and sugars) has been shown to lower blood pressure and cholesterol.
• Ask your provider if it's safe to exercise. In most cases you can continue to exercise, though your provider may recommend modifying the types of activities you do.
• Don't smoke
• Don't drink alcohol
• Manage stress, which can worsen high blood pressure

Are high blood pressure medications safe while pregnant?

Many high blood pressure medications are safe to take during pregnancy, but not all, so talk with your healthcare provider if you're on medication and you become or plan to become pregnant. A preconception visit is the ideal time to address your current medications and optimize your health prior to pregnancy.

Important: Don't stop taking your blood pressure medication during pregnancy unless your provider tells you to. Your provider will prescribe safe medications to help keep your blood pressure under control.

If you develop high blood pressure during pregnancy, talk with your provider about the best medication option for you. The risks of untreated high blood pressure are much higher than the risks of medication.

Managing high blood pressure during pregnancy

Most women with high blood pressure can have a normal, healthy pregnancy. To help manage your high blood pressure:

• Keep all your prenatal appointments so your provider can monitor you and your baby and spot any problems.
• Take your blood pressure medication as prescribed.
• Maintain a healthy lifestyle by eating well, exercising, and not smoking or drinking alcohol.
• Monitor your blood pressure between prenatal appointments if your provider recommends it. They can suggest a home monitoring device and show you how to use it. You can also take your blood pressure reading at a local pharmacy. When taking your blood pressure, take it at the same time every day, and use the same arm for every reading.

When should I call the doctor about high blood pressure during pregnancy?

If you're checking your blood pressure at home, contact your provider if your blood pressure is above a certain level. Your provider can tell you what those levels should be and what to do if you go above them.

Let your provider know immediately if you notice any changes in your baby's movements. If your baby seems less active than usual, you may need to do kick counts.

Also call your provider right away if you have any signs of severe preeclampsia or HELLP syndrome:

• A headache that's severe or doesn't go away
• Vision changes, including double vision, blurriness, seeing spots or flashing lights, light sensitivity, or temporary loss of vision
• Intense pain or tenderness in the upper abdomen or shoulder
• Chest pain
• Nausea or vomiting (other than morning sickness in early pregnancy)
• Difficulty breathing

Will I have high blood pressure after pregnancy?

Unless you have preexisting or chronic hypertension, your blood pressure will most likely return to a normal level within a few weeks after you have your baby.

After you give birth, your blood pressure will be closely monitored, and your caregiver will be watching you for signs of worsening hypertension and preeclampsia.

In some women, though, blood pressure remains elevated. If your blood pressure is still high three months after you give birth, you'll be diagnosed with chronic hypertension.

Learn more:

• I have hypertension. What do I need to know before I get pregnant?
• Pregnancy symptoms you should never ignore

Can preeclampsia happen at 15 weeks?

When should I worry about my blood pressure during pregnancy?

What causes high blood pressure in second trimester?

Is high blood pressure normal at 14 weeks pregnant?