High Blood Pressure During Pregnancy: What To Know

High blood pressure during pregnancy remains a leading cause of severe complications for pregnant women and their babies. Hypertension, also known as high blood pressure, affects 1 in every 12-17 pregnancies for women aged 20-44. It’s essential to understand hypertensive disorders of pregnancy, signs of high blood pressure, and potential complications, as well as proper management of high blood pressure during pregnancy and how to prevent it.¹

Blood pressure measures the force of blood within the arteries. As the heart contracts and relaxes, the blood pumps through your blood vessels, exerting a fluctuating pressure within the arteries. Readings consist of two numbers, the top (systolic) and the bottom (diastolic), and are measured in millimeters of mercury or mmHg. Regular, healthy blood pressure is less than 120 mmHg over 80 mmHg. If written out, it will look like 120/80 mmHg.^2,3

High blood pressure is considered anything over 120/80 mmHg. However, generally, the higher the blood pressure, the more emergent the situation becomes:²

• Elevated blood pressure includes a systolic number ranging from 120-129 mmHg over a diastolic number of less than 80 mmHg.
• Stage 1 hypertension includes a systolic number ranging from 130-139 mmHg or a diastolic between 80-89 mmHg.
• Stage 2 hypertension includes a systolic number of 140 mmHg or higher or a diastolic number of 90 or higher.
• A hypertensive crisis is a medical emergency and includes any systolic number of 180 mmHg or greater or a diastolic number greater than 120 mmHg.

The only way to know if you have high blood pressure is to measure it with a special monitor or cuff. Not all women experience symptoms, and it can be challenging to distinguish possible signs of high blood pressure from common pregnancy symptoms. However, if your blood pressure worsens, so can your symptoms.

The following are signs of high blood pressure during pregnancy:¹

• A headache that does not go away
• Vision changes, including blurred vision or vision loss
• Nausea and vomiting
• Upper abdominal pain
• Sudden weight gain
• Swelling in your face, hands, or legs
• Difficulty breathing

Types of High Blood Pressure Conditions Before, During, and After Pregnancy

The following conditions are known collectively as hypertensive disorders of pregnancy.

Chronic hypertension occurs when a woman has hypertension before pregnancy or develops it before 20 weeks gestation. Symptoms can be mild and go unnoticed, but it increases the risk of developing preeclampsia in the second and third trimesters.^1,3

Gestational hypertension occurs when a woman develops high blood pressure after 20 weeks gestation, and the kidneys, liver, or heart are unaffected. It usually goes away after giving birth but can progress to more severe preeclampsia.^1,3

Preeclampsia is severe hypertension in the latter half of pregnancy at over 20 weeks gestation. It is unique to pregnancy, and its exact cause is unknown. In rare cases, it can occur in the postpartum period.³

Preeclampsia increases the risk of severe complications to the health of the mother and baby and is one of the leading causes of preterm birth. Women with preeclampsia typically have protein in their urine, but not always.³

Blood pressures of 140/90 mmHg and evidence of organ damage are hallmarks of preeclampsia. Preeclampsia ranges from mild to severe, and medical interventions depend on the mother’s response to treatment. Healthcare providers will closely monitor both mother and baby; often, delivery of the baby is necessary if doctors cannot lower the blood pressure.^1,3

When preeclampsia becomes severe, it can cause seizures and lead to stroke, coma, or even death. Eclampsia refers to this rare but severe complication of preeclampsia.¹

High Blood Pressure Complications for Mother and Baby

Increasing blood pressure causes the heart to work harder to circulate blood throughout the body. It can also affect blood flow to the placenta, which nourishes your growing baby. Not all women with high blood pressure will have complications, and close monitoring can reduce the risks of life-threatening problems. Risks increase as blood pressure rises. Preeclampsia and eclampsia cause the most concern.^7,8

Risks of high blood pressure in pregnancy for the mother include:^7,8

• Organ damage: Kidney and liver damage can occur in preeclampsia.
• Seizures: Very high blood pressure can cause swelling in the brain leading to seizures.
• Placental abruption: The placenta detaches from the uterus before the baby is born. It is associated with heavy bleeding, hemorrhage and deprives the baby of oxygen. It is life-threatening and potentially fatal for both mother and baby.
• HELLP syndrome: Women with preeclampsia or eclampsia are at increased risk of this rare, life-threatening blood clotting disorder.
• Stroke: In extreme cases of preeclampsia/eclampsia, blood vessels can burst, causing a stroke.

Risks to the baby include:^7,8

• Intrauterine growth restriction: When blood flow to the placenta is decreased, the baby is deprived of nutrients and oxygen and does not grow as expected.
• Premature delivery: Sometimes, a baby must be delivered early if the mother or baby’s life is in danger or if the baby is not growing. A very premature baby can spend weeks to months in a neonatal ICU (NICU).
• Brain injury, cerebral palsy, or stillbirth: If the baby does not get enough oxygen or has a placental abruption, the risk of long-term injury or death increases.

Whether you have a history of high blood pressure before you become pregnant or if you develop it during pregnancy, it is essential to talk with your doctor about what to expect. You will want to ensure any medications you take are safe during pregnancy.

After their baby is born, women can still have high blood pressure postpartum. Make sure to listen to your body, follow any recommendations by your doctor, and seek emergency care if your blood pressure is high or you have symptoms of high blood pressure. When in doubt, seeking medical attention is better than delaying possible care.^1,3,6,7

To help prevent developing high blood pressure, you can:^7,8

• Maintain a healthy weight
• Eat a balanced diet
• Limit salt intake
• Get 30 minutes of exercise a day, like walking
• Avoid alcohol, smoking, and drugs

Prevention, early detection, and prompt, vigilant medical care can significantly improve outcomes for women experiencing high blood pressure during pregnancy.

Your doctor may prescribe medications to help keep your blood pressure under control, and low-dose aspirin is often a part of therapy, but you should only take aspirin if prescribed. Women with hypertension can expect to have more frequent prenatal visits. They may have additional monitoring by ultrasound, fetal heart rate monitoring, and close evaluation of their baby’s growth and movements. Home blood pressure monitors enable women to keep an accurate record for their providers and can identify when a hospital visit may be necessary. If your symptoms worsen, your doctor may recommend bed rest or even hospitalization. Sometimes women are admitted to the hospital and require IV medications to manage their condition and prevent seizures. Early diagnosis and treatment improve outcomes for mother and child.^5,7

If you experience symptoms of high blood pressure during your pregnancy, contact your provider immediately or seek emergency care. Time is valuable. Prompt treatment and follow-up can help ensure you and your child have the best outcomes.