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Pregnancy-Induced Hypertension: Causes, Symptoms And Treatment

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Pregnancy-induced hypertension or gestational hypertension affects approximately seven to ten percent of pregnancies in the US (1).

According to the American College of Obstetricians and Gynecologists (ACOG), gestational hypertension is blood pressure greater than or equal to 140mmHg systolic and 90mmHg diastolic pressure. These measurements should be obtained in two readings at least four hours apart after 20 weeks of pregnancy in a woman who previously had normal blood pressure (2).

Read this post to know about the types, causes, risk factors, symptoms, diagnosis, and treatment of pregnancy-induced hypertension.

What Are The Types Of Hypertension During Pregnancy?

Hypertensive disorders in pregnancy (HDP) is classified into the following categories (3) (4):

  • Chronic hypertension or pre-existing hypertension is high blood pressure before pregnancy or 20 weeks of pregnancy. This may increase the risk for preeclampsia in the second or third trimester, especially if left untreated. Chronic hypertension does not resolve after
  • Gestational hypertension is high blood pressure during pregnancy that is diagnosed after 20 weeks of gestation. Although this may resolve after pregnancy, gestational hypertension can increase future risk of chronic hypertension. It does not increase the amount of proteins in the urine (no proteinuria).
  • Preeclampsia is high blood pressure with proteinuria after 20 weeks of pregnancy. Any hypertensive disorder can cause preeclampsia. Some women with preeclampsia develop seizures called eclampsia. Both these conditions are medical emergencies.

The complications may vary in each category of hypertensive disorder, and the treatment and diagnostic tests are planned accordingly.

What Are The Signs And Symptoms Of Pregnancy-Induced Hypertension?

High blood pressure in the second half of pregnancy is the main symptom of pregnancy-induced hypertension. The following symptoms can also be associated with high blood pressure (5):

  • Vision changes such as double vision or blurred vision
  • Nausea
  • Vomiting
  • Less urine production (oliguria)
  • Pain in the upper right side and around the abdomen

Note that the symptoms and signs of gestational hypertension may vary among pregnant women, and some may not develop any symptoms.

What Are The Risk Factors And Causes Of Gestational Hypertension?

The exact cause of pregnancy-induced hypertension is unknown. However, the following factors may increase the risk of developing hypertension during pregnancy (4) (5):

  • Pre-existing high blood pressure (chronic hypertension)
  • Hypertension in previous pregnancies
  • Kidney diseases
  • Maternal age less than 20 or more than 40
  • Family history of gestational hypertension
  • Immune system disorders such as lupus
  • Overweight
  • African-American race

Some studies show that women who undergo in vitro fertilization (IVF) through frozen embryo transfer (both donor and autologous oocyte) and fresh donor embryo transfer have an increased risk of hypertensive disorders of pregnancy. The risk was not found in women who conceived through IVF, such as autologous oocyte or fresh embryo transfer (6).

Why Is Gestational Hypertension A Concern?

Resistance in the blood vessels increases when blood pressure increases. This can affect the blood flow to various organ systems in a pregnant woman, including the kidneys, brain, liver, uterus, and placenta.

Other complications of gestational hypertension may include (2) (7)

  • Placental abruption, the premature separation of the placenta from the uterine wall
  • Poor fetal growth (intrauterine growth restriction)
  • Stillbirth
  • Eclampsia
  • Preterm birth
  • Increased future risk of hypertension

Untreated severe gestational hypertension (blood pressure more than 160/110mmHg) can affect the mother and fetus. Early diagnosis and treatment can help control blood pressure in pregnancy and avoid these complications.

When Should You Call Your Doctor?

Call or visit your doctor promptly if you have any signs of high blood pressure. Symptoms such as persistent headaches, vision changes, swelling, and less urine should be evaluated. However, pregnancy symptoms can sometimes mask hypertension symptoms. Hence, seek your doctor’s advice for any persisting symptoms in pregnancy (8).

How Is Pregnancy-Induced Hypertension Diagnosed?

Gestational hypertension can be diagnosed by measuring blood pressure during pregnancy. Increased blood pressure on two readings at least four hours apart is required to diagnose the condition.

Clinical symptoms are not mandatory for diagnosis. The onset of symptoms may signify damage to the major organs supplied by the circulatory system, which is known as end-organ damage.

The following tests are also done in women with gestational hypertension (8) (9):

  • Urine testing for proteinuria
  • Assessment of edema
  • Weight measurement
  • Kidney and liver function tests
  • Blood clotting tests

Blood pressure, blood, and urine tests are evaluated more frequently in women with gestational hypertension. In addition to this, a fetal ultrasound, including biophysical profile, movement, and nonstress tests, is done to ensure fetal and placental well-being.

How Is Gestational Hypertension Treated?

Hypertension treatment depends on the symptoms, severity, stage of pregnancy, and health status. Treatment aims to prevent the worsening of the condition and complications. The treatment for gestational hypertension is as follows (10):

  • For pregnant women with a blood pressure of 140/90 to 159/109mmHg: Anti hypertensives are given to lower the blood pressure to 135/85mmHg, and hospitalization is optional. Blood pressure is measured once or twice a week. Other tests are done weekly, and fetal monitoring is done in two to four weeks.
  • For pregnant women with blood pressure above 160/110mmHg (severe hypertension): Hospitalization and antihypertensive treatment with blood pressure monitoring every 15 to 30 minutes are required until it lowers. Other lab tests are done daily, and fetal monitoring is done every two weeks until the blood pressure is under control.

Treatment with labetalol is often recommended. Nifedipine is prescribed for those who have problems with labetalol. If both these medications are not suitable, methyldopa is given. Doctors may opt for treatments based on the risks and benefits, fetal effects, maternal preferences, and side effects. Resting in hospital settings is not recommended to treat gestational hypertension.

What To Do For A Safe Delivery With Gestational Hypertension?

The following measures may help mothers with high blood pressure during pregnancy have a safe and healthy delivery (9):

  • Take hypertension medications as prescribed
  • Attend prenatal visits as recommended
  • Maintain a healthy, low-sodium diet
  • Follow the doctor’s advice regarding exercises and other activities
  • Plan early delivery if suggested

Women with a blood pressure of more than 160/110mmHg are recommended to have an early delivery depending on the maternal and fetal indications. In addition, antenatal corticosteroids and magnesium sulfates are prescribed before early delivery (10).

Is It Possible To Have High Blood Pressure After The Baby Is Delivered?

In most cases, gestational hypertension goes away after delivery. However, some women continue to have high blood pressure after delivery. In such cases, medications are given after delivery.

Doctors may change some medications, such as methyldopa, after delivery and ask to continue the same treatment regime until blood pressure normalizes. Chronic hypertension does not resolve after delivery, and medications have to be continued as recommended (10).

How To Prevent Pregnancy-Induced Hypertension?

Gestational hypertension cannot be prevented. However, the following methods may reduce the risk of developing HDP (11):

  • Maintain a healthy weight before conceiving
  • Eat healthily and exercise regularly
  • Control chronic hypertension before pregnancy with adequate treatment

The symptoms of gestational hypertension are evident only when the blood pressure is severely high and the organs are affected. Regular prenatal checkups help diagnose the condition and control it before complications develop. Gestational hypertension usually resolves after delivery, and early delivery is not routinely recommended.

References:

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Dr Bisny T. Joseph

Dr. Bisny T. Joseph is a Georgian Board-certified physician. She has completed her professional graduate degree as a medical doctor from Tbilisi State Medical University, Georgia. She has 3+ years of experience in various sectors of medical affairs as a physician, medical reviewer, medical writer, health coach, and Q&A expert. Her interest in digital medical education and patient education made... more