Types of high blood pressure

Chronic high blood pressure

Chronic (long-term) high blood pressure may have developed before the woman became pregnant or may develop during the early part of her pregnancy, before she is 20 weeks pregnant. There are two types of chronic high blood pressure.

  • Primary chronic high blood pressure, where the cause is not known. This is the most common type of high blood pressure.

  • Secondary chronic high blood pressure, which has a known medical cause (for example, a kidney disorder).

If you have secondary chronic high blood pressure your doctor should offer to refer you to a specialist for additional care during your pregnancy.

Gestational high blood pressure

Gestational high blood pressure (sometimes known as gestational hypertension) is a type of high blood pressure that develops in the later stages of pregnancy (after 20 weeks) and goes away within 6 weeks of the baby's birth.


Pre-eclampsia is a type of high blood pressure that develops after the woman is 20 weeks pregnant and goes away within 6 weeks of the baby's birth. Unlike women with gestational high blood pressure, women with pre-eclampsia have a lot of protein in their urine (known as proteinuria).

Women who are at higher risk of developing pre-eclampsia

If you are at higher risk of developing pre-eclampsia than other pregnant women, your doctor should advise you to take 75 mg of aspirin once a day from the time you are 12 weeks pregnant until you have your baby.

You are more likely to develop pre-eclampsia than other pregnant women if you have more than one of the following risk factors:

  • this is your first pregnancy

  • you are aged 40 or over

  • your last pregnancy was more than 10 years ago

  • you are very overweight

  • you have a family history of pre-eclampsia

  • you are carrying more than 1 baby.

Your risk of pre-eclampsia is also greater if any of the following apply to you:

  • you had high blood pressure before you became pregnant (chronic high blood pressure)

  • you had high blood pressure during a previous pregnancy

  • you have chronic kidney disease, diabetes, or an inflammatory disease that affects the immune system, such as lupus.

Questions to ask your doctor

  • What is pre-eclampsia?

  • How will I know if I have pre-eclampsia?

  • Can pre-eclampsia harm my baby?

  • Please tell me about the risks and benefits to me and my baby of taking aspirin.

  • Is there anything else I can do to prevent pre-eclampsia during my pregnancy?

  • How likely am I to develop pre-eclampsia?

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