Having high blood pressure (hypertension) at any time can lead to problems but especially so during pregnancy. It could have dangerous outcomes for you and your baby, particularly the risk of pre-eclampsia, if adequate care is not taken to control it effectively. With proper antenatal care, however, the risks can be greatly reduced.

If you consistently have a systolic blood pressure of 140 or more and a diastolic blood pressure of 90 or more, you will be said to be suffering from hypertension.

Types of Hypertension in Pregnancy

During pregnancy, hypertension can be of 4 types

  • Chronic hypertension (essential hypertension).
  • Transient hypertension, gestational hypertension, or pregnancy-induced hypertension.
  • Pre-eclampsia and eclampsia.
  • Superimposed pre-eclampsia.

Chronic Hypertension (Essential Hypertension)

Chronic or essential hypertension is high blood pressure which is present before conception, before 20 weeks of pregnancy and which continues throughout pregnancy and for more than 6 weeks after delivery. Chronic hypertension, at any time, can be dangerous if not controlled properly because of the risks associated with it such as heart attacks and stroke. During pregnancy, it can affect the developing baby, causing growth retardation. If you are planning a pregnancy, it would be ideal if your blood pressure could be brought to a normal level before conception. All through your pregnancy, your blood pressure will need to be monitored carefully so that you do not develop any complications which may harm you or the baby.

Gestational Hypertension

Sometimes, you develop high blood pressure for the first time during your pregnancy, without any previous history of hypertension. This transient hypertension or gestational hypertension usually occurs after mid-pregnancy or in the first 24 hours after birth of your baby, without other signs of pre-eclampsia, but it soon returns to normal following delivery. This type of hypertension needs to be monitored very carefully because it may lead to more serious complications of pregnancy such as pre-eclampsia and eclampsia. It may not always be possible to differentiate it from pre-eclampsia and is then treated as pre-eclampsia. Its importance lies in the fact that it often develops into essential hypertension later in life.

Pre-eclampsia and Eclampsia

Pre-eclampsia is a serious complication of pregnancy where high blood pressure is present along with swelling of the body (edema), especially of the hands and face, and protein in the urine. Pre-eclampsia occurs typically in the first pregnancy, after the 20th week of pregnancy, most frequently in the third trimester, towards the end of pregnancy. This condition may be further complicated by convulsions, occurring without any other cause, when it is known as eclampsia. Both these conditions are potentially harmful for you and your baby, especially because of the risk of preterm delivery.

Superimposed Pre-eclampsia

When pre-eclampsia develops in a woman already suffering from chronic hypertension, it is known as superimposed pre-eclampsia.

With hypertension during pregnancy it is often difficult to determine whether it is essential hypertension, superimposed pre-eclampsia or pre-eclampsia because the blood pressure normally decreases in the second trimester and this decrease may mask the presence of chronic hypertension.

Symptoms of Pre-eclampsia

In most women, hypertension does not produce any symptoms.
The symptoms of pre-eclampsia may be

  • Severe persistent headaches.
  • Problems with vision, such as blurring or photophobia (sensitivity to light).
  • Sudden weight gain over one or two days
  • Swelling (edema), especially of the face and hands, present on getting out of bed in the morning.
  • Abdominal pain.
  • Chest pain.
  • Vomiting.

Women at Risk of Pregnancy Hypertension

  • First pregnancy.
  • Overweight or obese before pregnancy.
  • Excessive weight gain during pregnancy.
  • Hypertension or pre-eclampsia in previous pregnancies.
  • Family history, with mother or sisters suffering from hypertension during pregnancy.
  • Multiple pregnancies, such as twins.
  • Women over 35.
  • Women suffering from hypertension or kidney disease prior to pregnancy.

Dangers of High Blood Pressure during Pregnancy

Having high blood pressure during pregnancy can be dangerous for you and your baby.

  • High blood pressure leads to less blood supply to the placenta, resulting in reduction of oxygen supply and nutrients to the baby. This may cause growth retardation and low birth weight of the baby.
  • Uncontrolled hypertension may lead to preterm delivery. The preterm delivery may be spontaneous or it may become necessary to induce delivery or go for a Cesarean section as the only means of controlling the high blood pressure and complications such as pre-eclampsia and eclampsia.
  • Hypertensive disorders in pregnancy can become life-threatening for mother and baby.
  • Increased risk of stillbirths.
  • Complications and reduced chances of survival of a preterm baby, especially if delivered long before the due date.
  • Abruptio placentae is a complication which may develop as a result of hypertension. The placenta separates from the uterus before delivery and can cause severe bleeding in the mother as well as depriving the baby of oxygen and nutrients.
  • Increased risk of gestational diabetes mellitus.

Importance of Prenatal Care

  • Routine prenatal care is essential because most women do not have any symptoms of hypertension. Routine blood pressure monitoring and testing urine for proteins can detect many such cases and help in better management.
  • A woman with known hypertension can reduce chances of complications during pregnancy by consulting her doctor prior to conception and following his advice regarding diet, exercise and medications so that her blood pressure can be brought under control.
  • During pregnancy, regular prenatal checkups of known hypertensive women will help to detect and treat any problems that may occur at the earliest. These women may need more frequent checkups than others, with blood pressure, weight and urine for proteins being checked during each visit.
  • Regular monitoring of the fetal heart rate and repeated ultrasonography will help to assess the well-being of the baby.

Treatment of Hypertension in Pregnancy

Treatment starts as soon as hypertension is detected. If you already have hypertension prior to pregnancy and would like to conceive, treatment starts from then on. Your doctor will advise you about weight reduction, if necessary. Rest, proper diet (including a salt-restricted diet) and adequate exercise are important.

You may continue with the antihypertensive drugs you are on or the doctor may prefer to change your medications to those most suitable for use during pregnancy. During your prenatal visits, if your blood pressure is found to be slightly increased and your delivery date is not too near, you may be advised bed rest, either at home or in the hospital.

If the blood pressure becomes too high or symptoms of pre-eclampsia develop, the doctor may have no other choice but to deliver the baby, even if it is preterm, because that is the only definitive treatment for pre-eclampsia. If no serious complications develop, your doctor may let you carry your pregnancy to term or may prefer to deliver the baby 2 to 3 weeks before your due date to avoid complications which are most likely to develop as you near term.