What causes high blood pressure in pregnant women

High blood pressure in pregnancy, or hypertension, is how much pressure is placed on the walls of arteries when the heart pumps blood. Blood pressure is measured with two numbers, the top number (systolic) and the bottom number (diastolic) and reads 120/80, for example. The systolic number measures blood pressure when the heart pumps the blood to organs, and the diastolic number measures blood pressure when the heart retracts to fill with blood again.

High blood pressure during pregnancy can cause complications for the mother and the baby including preeclampsia, preterm birth and placental abruption. 

Types of High Blood Pressure in Pregnancy

Even if you have not had high blood pressure before pregnancy, you can develop high blood pressure during pregnancy, called gestational hypertension. A blood pressure during pregnancy of 140/90 is considered high during pregnancy and a diagnosis of gestational hypertension is given. Severe high blood pressure in pregnancy is 160/110.

Types of hypertension in pregnancy include:

• Gestational Hypertension: High blood pressure that occurs during pregnancy, where high blood pressure was not chronic before the pregnancy began. This type of high blood pressure usually returns to normal soon after the baby is delivered.
• Chronic Hypertension: If you have had high blood pressure before pregnancy, or before 20 weeks into your pregnancy, you most likely have chronic hypertension.
• Chronic Hypertension with Superimposed Preeclampsia: High blood pressure that occurs during pregnancy can lead to preeclampsia; however, if high blood pressure was present before pregnancy and preeclampsia happens during pregnancy, the diagnosis is chronic hypertension with superimposed preeclampsia.
• Preeclampsia: If high blood pressure occurs after 20 weeks of pregnancy when no past chronic high blood pressure diagnosis has been given, and there is protein in urine and/or organs start to work improperly, preeclampsia is diagnosed.

What Causes High Blood Pressure in Pregnancy?

Because of the many changes and strains on the body that happen when pregnant, sometimes high blood pressure can occur in an otherwise healthy individual that has never experienced high blood pressure. 

High Blood Pressure Symptoms in Pregnancy

In some cases the symptoms of high blood pressure during pregnancy may be subtle or go unnoticed. Because many changes take place when pregnant, it is important to know the symptoms of high blood pressure. 

A blood pressure during pregnancy of 140/90 is considered high during pregnancy and a diagnosis of gestational hypertension is given. Severe high blood pressure in pregnancy is 160/110. A typical blood pressure is around 120/80.

Some signs of high blood pressure in pregnancy include:

• Severe headaches
• Nausea or vomiting
• Excess protein in urine (a urine sample is gathered at each doctor visit during pregnancy)
• Changes in vision
• Upper abdominal pain

Treatment Options for High Blood Pressure in Pregnancy

It is important to keep blood pressure down during pregnancy because of the potential complications for both mom and baby. There are several ways to reduce blood pressure during pregnancy including:

• Attend all prenatal checkups
• Take medication regularly, if prescribed
• Eat a healthy diet
• Exercise regularly
• Avoid smoking, drinking and substance abuse

Stress can also be a factor on the body during pregnancy so it is important to avoid stressful situations, if possible, and be sure to get enough rest. Breathing exercises, prenatal yoga, baths and prenatal massages are all ways to help beat stress and take care of the body while pregnant.

Risk Factors for High Blood Pressure in Pregnancy

There are many factors that can put you at risk for developing high blood pressure during pregnancy. Knowing these risk factors ahead of time can help you and your provider develop a treatment plan or prevention plan for high blood pressure during pregnancy.

Some risk factors for high blood pressure in pregnancy include:

• Being overweight
• Family history of high blood pressure
• Age
• Smoking
• Diet high in salt
• African American
• Diabetes or kidney disease
• A sedentary lifestyle

These risk factors put you at greater risk of developing high blood pressure during pregnancy, which can lead to pregnancy complications.

A small percentage of pregnant women in the U.S. have high blood pressure at some point during their pregnancy. Some cases are mild; other cases are severe. Treatment varies depending on the type you have and how far along you are in your pregnancy.

There are three main types of high blood pressure during pregnancy:

• Chronic hypertension. This is high blood pressure you had before you became pregnant. It can also refer to high blood pressure you get before the 20th week of pregnancy. Sometimes you may have high blood pressure for a long time before becoming pregnant but don’t know it until your first prenatal visit with your doctor. Chronic hypertension can lead to serious problems, including preeclampsia. This type of high blood pressure continues after you have your baby.
• Gestational hypertension. This is high blood pressure you get after your 20th week of pregnancy. Most of the time, this hypertension doesn’t hurt you or your baby. You may not even have other symptoms. However, sometimes this type of hypertension is severe. It can cause your baby to be born smaller than normal (have a low birth weight). Your baby may even be born early because of it. It can lead to preeclampsia. And while it usually goes away within three months of giving birth, it can raise your risk of getting high blood pressure in the future.
• Preeclampsia. This is a sudden rise in your blood pressure after your 20th week of pregnancy, typically in your third trimester. It also may cause damage to your liver, kidneys, or brain. You may have seizures. You may have significant swelling in your legs and sometimes your arms and face. This condition is serious. It can hurt both you and your baby, and even be life threatening. Some women get preeclampsia after they deliver their baby. This is called postpartum preeclampsia.

In some cases, high blood pressure during pregnancy can cause harm to you and your baby.

• You may develop gestational diabetes.
• You may experience problems with your heart or kidneys. You’re also at greater risk for a stroke.
• High blood pressure may prevent the placenta from getting enough blood. (The placenta gives oxygen and food to your baby.) If the placenta doesn’t get enough blood, your baby doesn’t get enough oxygen and food. This can cause low birth weight and premature birth.
• High blood pressure can lead to placental abruption. This is when the placenta becomes unattached to the uterus. This can be a life threatening situation to both you and your baby.