High Blood Pressure During Pregnancy

Blood pressure is the amount of pressure of blood against the blood vessel walls every time the heart contracts. High blood pressure, or hypertension, can lead to health problems and if present during pregnancy, can cause complications for a mother and child.  Chronic hypertension is high blood pressure that was present before pregnancy or that occurs in the first half of pregnancy. Gestational hypertension is high blood pressure that develops in the second half of pregnancy. Although gestational hypertension usually goes away after birth, it can increase the risk of developing hypertension in the future. Preeclampsia is a serious blood pressure disorder that occurs when hypertension develops after 20 weeks of pregnancy, with signs of damage to other organ systems, including the kidneys, liver, blood or brain.

High blood pressure during pregnancy poses various risks, including:

• Decreased blood flow to the placenta: If enough blood doesn’t flow to the placenta, your baby may receive less oxygen and fewer nutrients. This can lead to slow growth, low birth weight or premature birth.
• Placental abruption: Preeclampsia increases the risk of the placenta separating from the inner wall of the uterus before delivery. Severe abruption can cause heavy bleeding, which can be life-threatening for you and your baby.
• Intrauterine growth restriction: Hypertension can result in slowed or decreased growth of your baby.
• Injury to other organs: Poorly controlled hypertension can result in injury to your brain, heart, lungs, kidneys, liver and other major organs.
• Premature delivery: An early delivery may be necessary to prevent potentially life-threatening complications.
• Future cardiovascular disease: Preeclampsia can increase your risk for future high blood pressure, stroke, heart disease and cardiovascular kidney disease.

How Often Does High Blood Pressure During Pregnancy Happen?

Hypertensive disorders effect 5 to 10 percent of pregnancies. About 70 percent are first-time pregnancies.Preeclampsia affects around 3 percent of pregnancies.

What Are Some Symptoms of High Blood Pressure During Pregnancy?

High blood pressure generally doesn’t have any noticeable signs or symptoms. Your blood pressure will need to be checked to determine if it is high. Blood pressure that is 140/90 mm Hg or greater, documented on two occasions, at least four hours apart, is abnormal.

Preeclampsia, however, does have some noticeable symptoms, including:

• Swelling of face or hands
• Persistent headache
• Seeing spots, or changes in eyesight
• Pain in the upper abdomen
• Nausea and vomiting in the second half of pregnancy
• Chest pain
• Difficulty breathing

What Are Some Causes of High Blood Pressure During Pregnancy?

Some of the possible causes of high blood pressure during pregnancy include:

• Being overweight or obese
• First-time pregnancy
• Family history of pregnancy-related hypertension
• Carrying more than one child
• Age over 40
• Assistive technology such as IVF
• Other medical issues, such as diabetes or inflammatory conditions

How Can High Blood Pressure During Pregnancy Be Treated?

Your doctor can determine if you have high blood pressure during your pregnancy. You may be asked to measure your blood pressure at home. To track your blood pressure at home, blood pressure monitors are available for purchase from pharmacies and medical goods stores. Not all automated machines are validated for pregnancy, and you may be asked to bring in your machine to compare it with one at your doctor's office.  

During pregnancy, your doctor may prescribe certain medications, including:

• Antihypertensives: Several medications for high blood pressure can be used safely during pregnancy and breastfeeding. Commonly used medications include labetalol and nifedipine. Talk to your doctor before taking any over-the-counter medications to learn how they might affect your blood pressure. 
• Baby aspirin and calcium: These can reduce the risk of developing preeclampsia. If preeclampsia does develop, managing blood pressure and watching carefully for symptoms is key.

After birth, maintaining a healthy lifestyle will also help manage your high blood pressure. Some good healthy habits include:

• Eating a healthy diet. Changing what, how often, and how much you eat can help keep your blood pressure in a healthy range. Ask to speak with a registered dietitian to determine an individualized healthy eating plan.
• Getting regular exercise. Regular, moderate exercise during pregnancy helps control your blood pressure. Aim for at least two and a half hours a week of moderate exercise, or 30 minutes a day, 5 days a week. Talk with your doctor before you start exercising to determine the best workouts for you that won’t place too much stress on your lower body.
• Knowing what’s off limits. Avoid alcohol, cigarettes, and any other illicit drugs. Talk to your doctor before taking any over-the-counter medications to learn how they might affect your blood pressure.

When Should I See My Doctor for High Blood Pressure During Pregnancy?

Your doctor will determine if you have high blood pressure during your pregnancy. If you do, you should be monitored closely by your health care team throughout your pregnancy. Your weight and blood pressure should be checked at every visit, and you might need frequent blood and urine tests.

If necessary, your doctor may prescribe the safest medication at the most appropriate dose. Take the medication exactly as prescribed. Don't stop taking the medication or adjust the dose on your own.

If you are monitoring your blood pressure at home, notify your doctor immediately if you have repeated high blood pressure readings that are four hours apart, or show any symptoms of preeclampsia.

Learn more about Multidisciplinary Obstetric Medicine Service (MOMS) at Brown University Health