What Is Hypertension In Pregnancy?

Blood pressure is the amount of force exerted by the blood against the walls of the arteries and when the pressure readings are higher than 140 over 90, a patient is considered to have hypertension or high blood pressure. Long term hypertension contributes to the development of coronary heart disease, stroke, heart failure and kidney disease.

Pre-Existing or Chronic Hypertension

Women who have pre-existing or chronic hypertension are more likely to have certain complications during pregnancy. The most common form of this hypertension is called Primary Chronic Hypertension where the cause is not known. Secondary Chronic Hypertension has a known medical cause (for example a kidney disorder). If you already take drugs to control chronic high blood pressure prior to pregnancy, you will need to consult your obstetrician to check whether these are safe to continue taking during your pregnancy.

Gestational Hypertension

However, some women can develop high blood pressure in the latter part (after 20 weeks) of pregnancy, known as gestational hypertension. Women can suffer from mild, moderate or severe gestational hypertension. Moderate to high blood pressure in pregnancy can become dangerous to both mother and foetus, although many pregnant women with high blood pressure can deliver healthy babies without complications.


Women with chronic hypertension and moderate to severe gestational hypertension need to be regularly monitored and tested by their gynaecologist , to ensure that this condition does not progress into a most extreme form of hypertension called preeclampsia or “toxaemia of pregnancy,” which can be life threatening to both mother and baby.

How Will Hypertension Impact On My Pregnancy?

Hypertensive diseases of pregnancy are amongst the leading causes of direct maternal deaths. The effects of hypertension range from mild to severe and in severe cases it can cause low birth weight, premature delivery and harm to the mother’s kidneys and other organs. For approximately two thirds of women who develop gestational hypertension, their blood pressure will return to normal about six weeks after birth.

Transient or gestational hypertension in late pregnancy however, is an indicator of chronic high blood pressure, cardiovascular disease and stroke in later adult life and is associated with a twofold risk with the onset of gestational diabetes mellitus, with an even higher risk if the mother is overweight.

Modifications in lifestyle and regular blood pressure control are recommended after delivery to reduce complications in subsequent pregnancies and lessen maternal cardiovascular risks in later life.

Women with moderate to severe hypertension may also benefit from referral to a hypertension sub specialist, and/or a perinatologist throughout the remainder of their pregnancy.

How can I Lower the Risk of Hypertension in Pregnancy?

If you are already taking medication for chronic hypertension and you are planning to become pregnant or have just found out that you are pregnant, your doctor may review your medication and advise altering dosages and/or switching to a different type of BP drug until after you’ve had the baby.

You should also:

  • Limit the amount of salt in your diet to help reduce blood pressure
  • Participate in regular physical activity
  • Lose weight if you are overweight
  • Because there isn’t sufficient evidence to support their role in lowering hypertension it is recommended that you do not take supplements such as folic acid, magnesium, vitamin A & E, fish and algal oils or garlic without advice from your doctor.
  • Discuss with your doctor how hypertension might affect you and your baby during pregnancy.

While you are pregnant:

  • Obtain regular prenatal care
  • Avoid alcohol and tobacco
  • Talk to your doctor about any over-the-counter medications you are taking or are thinking about taking.