High Blood Pressure During Pregnancy: What You Need To Know

Around 5—10%¹ of pregnancies are affected by hypertension (high blood pressure), either because the woman had chronic hypertension before becoming pregnant or developed the condition during pregnancy. High blood pressure during pregnancy is a serious health risk for mother and baby and can be life-threatening or fatal in some cases.

Hypertension before, during, and after pregnancy is preventable and treatable. You will be closely monitored throughout your pregnancy and birth to ensure you and your baby are safe and healthy, but the condition may impact your experiences, especially when it comes to giving birth. It helps to be aware of the steps you can take and the changes you can make to keep your blood pressure in check during your pregnancy and avoid serious complications.

What is high blood pressure?

High blood pressure occurs when too much pressure is exerted on the arteries as they carry blood away from your heart to other parts of your body. Over time, this pressure can damage your arteries and organs, leading to serious health conditions like stroke and heart failure.

A blood pressure reading has two numbers:

1. Systolic blood pressure (the first number) is a measurement of the highest pressure in your arteries when your heart pumps.

2. Diastolic blood pressure (the second number) is a measurement of the lowest pressure in your arteries when your heart is resting between pumps.

What is normal blood pressure?

A normal blood pressure reading (in pregnant and non-pregnant women) is 120mm Hg systolic and 80mm Hg diastolic (written as 120/80mm Hg). If your blood pressure is consistently higher than this, you may have hypertension.

Your doctor will take a baseline blood pressure reading during your first prenatal visit and your blood pressure will be monitored in all visits thereafter. A blood pressure reading exceeding 130/90mm Hg during pregnancy is a concern, and 140/90mm Hg is considered very high. If your blood pressure is this elevated, seek medical attention.

Types of high blood pressure during pregnancy

Several different high blood pressure categories can be seen in pregnant women, including:

Chronic hypertension

Women who had high blood pressure before pregnancy or develop it within the first 20 weeks of pregnancy have chronic hypertension. They may have already been receiving treatment and will need ongoing medical support throughout the pregnancy and beyond to prevent complications.

Gestational hypertension

If your blood pressure rises after 20 weeks gestation or close to your delivery date and you had no history of hypertension before pregnancy, you might be diagnosed with gestational hypertension. Unlike preeclampsia, gestational hypertension does not cause excess protein in the urine (proteinuria) or problems with your heart or kidneys.

Preeclampsia

Preeclampsia is characterized by a sudden increase in blood pressure that occurs in the last trimester. The condition is more likely to affect pregnant women with chronic hypertension, kidney disease, diabetes, and autoimmune conditions, and your risk is higher if you had preeclampsia in previous pregnancies.

Symptoms of preeclampsia include very high blood pressure and protein in the urine. Untreated, the condition can be life-threatening to both the mother and baby.

What causes high blood pressure in pregnancy?

Several factors² increase your risk of all types of high blood pressure during pregnancy, including:

• Smoking

• Obesity

• Sedentary lifestyle

• Alcohol use

• High salt intake

• Pregnancy over the age of 35

• Kidney disease 

• Diabetes

• Family history of hypertension

• Being Black or Hispanic

• Assisted reproduction, such as in-vitro fertilization (IVF)

Research shows that you could be more likely to develop preeclampsia³ if you had diabetes before this pregnancy, have obesity, are carrying multiple babies, this is your first pregnancy, or you had the condition in a previous pregnancy. Having chronic hypertension also raises your risk of developing preeclampsia.

What are the symptoms of high blood pressure during pregnancy?

The American Heart Association (AHA) calls high blood pressure a silent killer⁴ because most people don’t develop noticeable symptoms. That’s why you have a blood pressure reading taken at most (if not all) medical appointments and why blood pressure monitoring is so important in prenatal care.

The body undergoes many changes during pregnancy, so it’s easy to miss potential signs of high blood pressure because you think they’re “normal.” Keep the following symptoms in mind and speak to your doctor if you have them.

• Nausea and vomiting

• Upper abdominal pain

• Swollen ankles and feet

• Severe headache

• Rapid weight gain

Weight gain is an important indicator of high blood pressure during pregnancy, so you should monitor your weight carefully. If you gain more than 2.2 kg in a week, this could be a sign that you have developed preeclampsia.

Symptoms of preeclampsia

The following are the most common signs and symptoms of preeclampsia:

• Unfading headache

• Excess protein in the urine

• Upper right abdominal or shoulder pain

• Vision problems such as seeing spots and blurred vision 

• Swelling in the face, hands, feet, and ankles

• Extreme high blood pressure

• Sudden, rapid weight gain 

• Nausea and vomiting

Some pregnant women with preeclampsia don’t have protein in their urine — a condition called atypical preeclampsia⁵.

What are the risks of hypertension during pregnancy?

If high blood pressure during pregnancy is not treated early enough, there is a risk of complications for you and your baby. Fortunately, with proper treatment and management, most pregnant women with hypertension deliver healthy babies. Note that women with hypertension during pregnancy are more likely to have a cesarean section delivery⁶ than women with normal blood pressure.

High blood pressure risks during pregnancy can cause serious complications, including:

Reduced blood flow to the placenta

Hypertension can reduce blood flow to the placenta, limiting the delivery of nutrients and oxygen to your baby. This contributes to slow growth and can cause premature birth or low birth weight. If you deliver your baby prematurely, the risk of infection, breathing problems, and other related complications is higher.

If your doctor suspects blood supply to the placenta is limited, they may recommend early delivery.

Placental abruption

This is a medical emergency where the placenta prematurely disconnects from the uterus wall, depriving the baby of blood carrying oxygen and nutrients.

Injury to organs

High blood pressure can damage your lungs, brain, heart, liver, kidneys, and other vital organs.

HELLP syndrome

This is a severe form of preeclampsia characterized by low platelets, the destruction of red blood cells, and increased liver enzymes in the blood. Symptoms of HELLP syndrome include upper right abdominal pain, nausea, vomiting, and headache. HELLP can be a life-threatening condition and requires immediate medical attention to avoid organ damage.

Eclampsia

Eclampsia is a rare and dangerous condition that affects some women with preeclampsia. The condition can cause the mother to have seizures, which places her and the baby at risk.

Future high blood pressure

Hypertension during pregnancy, specifically preeclampsia, can increase your risk of developing high blood pressure again in the future⁷. High blood pressure can lead to serious health problems, including cardiovascular disease and stroke.

The risk is higher if you develop preeclampsia in more than one pregnancy or if you had a premature birth due to hypertension in the past.

Does high blood pressure affect labor and birth?

Your medical team will monitor the baby’s heart continuously during labor. You will probably have medication and fluids delivered via an IV during labor, delivery, and sometimes after birth. If your condition worsens, your medical team may consider an emergency cesarean section delivery.

How hypertension during pregnancy is diagnosed

Your blood pressure will be monitored during prenatal visits and you will undergo a few other tests and checks, including:

• Testing your urine for excess protein

• Taking a blood pressure reading along with your other vital signs like heart rate, respiratory rate, and temperature

• Weighing you to determine if you’re gaining weight at a normal rate

If your doctor detects high blood pressure, they will recommend more frequent visits to monitor both you and your baby. You will also undergo additional testing, including:

• Fetal ultrasound to check your baby’s amniotic fluid, placenta, development, and growth

• Electronic fetal heart monitoring to evaluate your baby’s heart rate and rhythm

• Doppler ultrasound to determine if there is enough blood flow to the placenta

A blood test will be ordered to monitor your blood cells and liver and kidney function if you are diagnosed with preeclampsia.

How is hypertension during pregnancy treated?

Treatment for high blood pressure during pregnancy⁸ depends on several factors, including:

• Severity of hypertension

• Stage of pregnancy

• Presence and severity of preeclampsia

• Level of risk to you and your baby

• When hypertension started

• Cause of hypertension

• Other medical problems

In addition to close monitoring and testing, you will likely be started on pregnancy-safe medication⁹ to help keep your blood pressure in check. Taking the right medication and controlling your blood pressure helps lower your chances of heart attack, stroke, HELLP syndrome, and other severe complications that can put you and your baby at risk. Remember to keep taking your medication until your doctor tells you to stop, and don’t adjust the dose on your own.

If you were already taking medication to treat chronic hypertension, your doctor might prescribe something different. This is because some conventional blood pressure medications are not recommended during pregnancy as they cross the placenta and potentially harm the baby.

If your blood pressure is still too high and you develop preeclampsia or other complications, your doctor may recommend a cesarean section or induce labor to reduce the risk to you and your baby.

Managing chronic hypertension during pregnancy

If you have already been diagnosed with chronic hypertension, get regular prenatal care early and make sure your doctor is aware of your condition and your history of hypertension. They may ask you to come in for more frequent check-ups to monitor your blood pressure and the health of you and your baby.

You may be asked to keep track of your blood pressure at home and present your readings when you visit the clinic. If you start taking a new medication, take it as prescribed and don’t mix it with other over-the-counter drugs, change the dose, or discontinue it without consulting your doctor. Generally, pay attention to how you feel and inform your doctor of any unusual changes.

Lifestyle strategies for managing hypertension during pregnancy

Your doctor will likely recommend lifestyle changes to help control your blood pressure during pregnancy, including:

Maintaining a healthy weight gain

Although you can expect to gain weight during pregnancy as your body changes and your baby grows, being overweight increases your chance of developing hypertension. Your doctor will keep a close eye on your weight as your pregnancy progresses.

Sticking to a healthy diet and regular exercise is always best for your overall health and can help you avoid high blood pressure before, during, and after pregnancy.

Remember, if you gain weight rapidly and unexpectedly during pregnancy, this could suggest you have preeclampsia.

Getting regular exercise

Moving your body is an essential part of maintaining a healthy weight and blood pressure before, during, and after pregnancy. Guidelines recommend getting at least 150 minutes of exercise a week¹⁰, but your ability to exercise may change as you progress through your pregnancy. Your doctor can give you advice about pregnancy-safe exercises and suggest ways to adapt your routine to ensure you’re keeping your body moving while protecting yourself and your baby.

Consuming enough potassium

Consuming too little potassium¹¹ in your diet, particularly with too much salt, can increase your risk of high blood pressure. Potassium counteracts the effects of salt, which prevents your body from expelling as much water. With increased water retention comes elevated blood pressure.

Try including some of these potassium-rich foods in your diet:

• Beans

• Green, leafy vegetables

• Fruits such as avocados, apricots, melons, and bananas

• Nuts and seeds

• Salmon and tuna

Avoiding alcohol and smoking

Alcohol and nicotine can raise your blood pressure and cause other complications during pregnancy for you and your baby.

Limiting salt intake

Excess salt in your diet can cause elevated blood pressure and swelling, so it’s important to watch your salt intake during pregnancy and keep it within the recommended range.

Research¹² has found that Americans consume too much salt on average, mostly from restaurant meals and processed pre-packaged foods. To avoid overconsuming salt during pregnancy, try to cook fresh meals at home as much as possible and use herbs and spices to add flavor to your meals.

Managing stress

Stress¹³ can raise your risk of developing hypertension, and over a long period, it can cause repeated blood pressure spikes that damage your body. Pregnancy causes significant physical and psychological changes that can affect your stress levels, and while it’s not always possible to remove all stressors from your life, you can learn to manage your stress in different ways.

Listening to calming music, taking a walk, or watching a funny movie can help you feel more relaxed. Other remedies include guided imagery, deep breathing, practicing yoga, and meditation.

Will my blood pressure return to normal after birth?

If you are diagnosed with gestational hypertension or preeclampsia, your blood pressure may return to normal after the delivery (note that this is more common in cases of gestational hypertension).

If you have complications, your medical team may keep you in the hospital for close monitoring and treatment after your baby is born.

Pregnant women with chronic hypertension need to have their blood pressure checked frequently after delivery to ensure it returns to safe levels and inform any medication adjustments before they are discharged.

When to see a doctor

Severely high blood pressure (exceeding 140/90mm Hg) sometimes causes symptoms such as vision changes, headache, abdominal pain, swelling in your face or hands, nausea and vomiting, and pelvic or abdominal pain. Call your doctor right away if you experience any of these symptoms or you get a significantly elevated blood pressure reading at home.

Share your doctor’s contact information with a family member or friend so they can call for help if you have a seizure or loss of consciousness.

The lowdown

Hypertension during pregnancy is a serious condition that requires close monitoring and, sometimes, treatment. You can either develop high blood pressure during pregnancy or have a previous history of chronic hypertension that continues during your pregnancy.

Hypertension-related complications are the second-leading cause¹⁴ of maternal death in pregnant women in the US, so it is something to pay close attention to.

High blood pressure during pregnancy can be managed and treated with medication and lifestyle changes, including eating a healthy diet with attention to salt and potassium intake, exercising regularly, managing stress and weight gain, and avoiding alcohol and smoking. Attend all your scheduled follow-up appointments so that you and your baby can be monitored throughout the pregnancy for optimal care.