Pregnancy Guide


During pregnancy your blood pressure and urine will be checked at every antenatal appointment. This is because a rise in blood pressure or protein in the urine can be the first sign of pre-eclampsia.

Although pre-eclampsia usually presents as high blood pressure (pregnancy-induced hypertension) and protein in the urine (pre-eclamptic toxaemia), it can present in other ways. See symptoms of pre-eclampsia.

Pre-eclampsia affects mum and baby

Pre-eclampsia can run in families, and affects around 3-5% of pregnancies. Problems usually start towards the end of pregnancy, after around week 28, but can occur earlier. It can also happen after the birth. It is likely to be more severe if it starts earlier in pregnancy.

Although most cases of pre-eclampsia are mild and cause no trouble, the condition can get worse and be serious for both mother and baby.

It can cause fits (seizures) in the mother, which is called eclampsia. It can also affect the baby's growth. If you develop pre-eclampsia, you will be offered regular ultrasound scans to check your baby's growth and health.

Pre-eclampsia is life threatening for mother and baby if left untreated. That is why routine antenatal checks are so important to look for pregnancy-induced hypertension and protein in your urine (proteinuria).

Many women with high blood pressure can hope for a vaginal delivery after 37 weeks. But if you have severe pre-eclampsia, it may be necessary to deliver your baby early, possibly by caesarean section.

Risk factors for pre-eclampsia

If you are at higher risk of pre-eclampsia, you should be advised to take 75mg of aspirin a day from 12 weeks of pregnancy until your baby is born to reduce your risk of developing pre-eclampsia.

You are considered higher risk if you have one or more 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 one baby

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

  • you had high blood pressure before you became pregnant
  • you had high blood pressure in a previous pregnancy
  • you have chronic kidney disease, diabetes, or a disease that affects the immune system, such as lupus

Symptoms of pre-eclampsia

There are usually no symptoms to warn you that you have hypertension or pre-eclampsia, and often the only way it can be detected is during the routine blood pressure and urine checks made by your midwife.

If you do have pre-eclampsia, you will probably feel well. If you get symptoms, these might be:

  • bad headaches
  • problems with vision, such as blurred vision or lights flashing before your eyes
  • pain just below the ribs
  • vomiting
  • sudden swelling of the face, hands and feet

However, you can have severe pre-eclampsia without any symptoms at all. If you get any of the symptoms listed above, or have any reason to think you have pre-eclampsia, contact your midwife, doctor or the hospital immediately.

Treatment of pre-eclampsia

Women with pre-eclampsia need admission to hospital, and often medicines to lower their high blood pressure. Occassionally, pre-eclampsia is a reason to deliver the baby early - you may be offered induction of labour or a caesarean section.

Monitoring pre-eclampsia

It is vital to go to all your antenatal appointments, or to reschedule them if you can't make them, as severe pre-eclampsia can affect both your health and your baby's health.

If left untreated, it can put you at risk of a stroke, impared kidney and liver function, blood clotting problems, fluid on the lungs, and seizures. Your baby may also be born prematurely or small, or even stillborn.

While the root cause of pre-eclampsia is not known, studies suggest the risk is higher if you are overweight when you become pregnant, so it's a good idea to reach a healthy weight before trying for a baby.

It is also more common if you have high blood pressure before becoming pregnant, or have had pre-eclampsia in a previous pregnancy. If this applies to you, attending regular check-ups to have your blood pressure and urine tested is even more important.

You can find information and support at the Action on Pre-eclampsia (APEC) website.

Last Updated: 08/11/2017 13:25:34
The information on this page has been adapted by NHS Wales from original content supplied by NHS UK NHS website