Pre-eclampsia

Pre-eclampsia is a serious condition and it can affect both you and your baby. The main feature is high blood pressure, but for a diagnosis of pre-eclampsia there must also be evidence that other organs are involved (such as protein in your urine).

Key points

  1. If you develop pre-eclampsia, the placenta does not develop normally, so you are monitored for this condition throughout pregnancy.
  2. Pre-eclampsia often develops without any symptoms. If you have any of the warning signs or symptoms listed below, see your doctor or lead maternity carer (LMC) straight away.
  3. If you have an increased chance of developing pre-eclampsia, such as having had it before, you may be prescribed a low dose of aspirin (100 milligrams) once a day from 12 weeks of pregnancy. 
  4. If you develop pre-eclampsia you may be admitted to hospital to be monitored closely. You may need to have your baby early.
  5. You and your baby will be well monitored and supported throughout.

What is pre-eclampsia?

Pre-eclampsia is a condition that only occurs during pregnancy and up to 2–3 weeks after delivery.

The main feature is high blood pressure, but for a diagnosis of pre-eclampsia there must also be evidence that other organs are involved, such as protein in your urine. Your kidneys, liver, brain, placenta and blood clotting system are the organs most commonly affected by pre-eclampsia.

 

What are the signs and symptoms of pre-eclampsia?

Pre-eclampsia often develops without any symptoms. The first signs are usually a rise in blood pressure and the presence of protein in your urine. These signs are normally picked up during an antenatal visit.

In some women with severe pre-eclampsia, signs and symptoms may include:

  • ongoing, persistent or severe headache
  • changes in eyesight such as seeing spots, flashing lights or floaters, blurry vision
  • pain in your upper belly, tummy area or shoulder
  • sudden and new swelling in your face, hands or eyes (some feet and ankle swelling is normal during pregnancy)
  • sudden weight gain (more than 1 kg in a week or more than 3 kg in a month)
  • vomiting later in your pregnancy (not the morning sickness of early pregnancy)
  • difficulty breathing.

Seek medical advice immediately if you develop any of these symptoms during your pregnancy.

What are the causes of pre-eclampsia?

The exact cause of pre-eclampsia is not understood, but in women who develop pre-eclampsia the placenta does not develop normally.

Although you may not show signs of pre-eclampsia until after 20 weeks of pregnancy, tests can be done as early as 12 weeks that show whether you are at risk of developing the condition. If you are at risk, you would be watched more closely to delay or prevent the development of pre-eclampsia. 

Who is at risk of developing pre-eclampsia?

The chance of developing pre-eclampsia is higher in women who:

  • have had pre-eclampsia before
  • are first time mothers or if it has been more than 10 years since your last baby
  • have a sister or mother who had pre-eclampsia
  • have high blood pressure before getting pregnant (pre-existing hypertension)
  • have certain medical conditions such as kidney disease or diabetes
  • are overweight
  • are 40 years or older
  • are expecting more than one baby (twins, triplets, etc)
  • had in vitro fertilisation (IVF).

If you have an increased chance of developing pre-eclampsia, you may be prescribed a low dose of aspirin (100 milligrams) once a day from 12 weeks of pregnancy. 

Most women who have these conditions do NOT develop pre-eclampsia. You may, however, be suitable for aspirin treatment and should have your blood pressure taken carefully at each visit. You should also be on the watch for any of the signs or symptoms of pre-eclampsia and report these to your LMC.

Many women who develop pre-eclampsia have none of these risk factors, so all pregnant women still need to have your blood pressure and urine checked each visit.

How can pre-eclampsia affect my baby or me?

Having pre-eclampsia can be a concern for both you and your baby. The more severe your pre-eclampsia is and the earlier it occurs in your pregnancy, the greater the risks for you and your baby. 

Risks to you as the mother include:

  • damage to your kidneys or liver
  • a greater chance of having a stroke
  • an increased risk of blood clotting problems
  • a chance of developing placental abruption (risk of severe bleeding from your placenta)
  • developing eclampsia (having seizures).

Risks to your baby include:

  • poor growth
  • an increased risk of premature birth (born before 37 weeks)
  • an increased chance of stillbirth.  

How is pre-eclampsia treated?

Once you have developed pre-eclampsia, it won’t go away until after your baby is born. If you develop pre-eclampsia, you will be referred to an obstetrician or specialist for tests and checks and may require admission to the hospital.

Treatment for pre-eclampsia is aimed at prolonging the pregnancy until your baby is big and developed enough to be born safely without too much risk to the mother or the baby during that time. If your baby does need to be born early because of complications there are treatments that can decrease the risks for your baby from being born prematurely. Read more about premature birth.

Treatment options for pre-eclampsia include:

Rest and gentle activity

Traditionally, continuous bed rest was recommended for all women with pre-eclampsia, but research has not shown a benefit from this. Actually, ongoing bed rest and lack of activity can increase your risk of blood clots. So for most women, continuous bed rest is no longer recommended but it is a good idea to limit your activity, avoid stress and rest now and again throughout the day. 

Hospitalisation

Severe pre-eclampsia may require you to say in hospital. In the hospital, your doctor will do regular tests and checks to monitor your baby's wellbeing and measure the volume of amniotic fluid. A lack of amniotic fluid is a sign of poor blood supply to your baby.

Medication

Aspirin

Aspirin has been shown to decrease the chances of a pregnant woman developing pre-eclampsia by about 10%. In other words, it will stop 1 out of 10 pregnant women from getting pre-eclampsia. The dose used is much smaller than the dose you would use for treating a headache, so it is called low-dose aspirin.

Although aspirin is very safe at low doses, no medications should be used in pregnancy unless there is a good reason.

If you think you might benefit from aspirin treatment,  talk to your doctor. Aspirin needs to be started before 20 weeks and ideally at 12 weeks to have the best effect. Aspirin does not seem to be of any benefit once pre-eclampsia has been diagnosed and is usually stopped before delivery.

Antihypertensives

If your blood pressure rises too high you will normally be prescribed medication to lower it (called antihypertensives). Your doctor will choose an antihypertensive that is considered safe in pregnancy.

Having your blood pressure lowered by a hypertensive does not mean your pre-eclampsia has gone. The blood pressure medication keeps you safe while you wait for your baby to become more mature and better able to cope with the stress of delivery.

Examples of antihypertensives that are commonly used to treat pre-eclampsia include:

To ensure that the medication is working, your doctor will monitor your blood pressure regularly and may adjust your medication dose if necessary.

If your blood pressure drops too low, then the blood flow to the placenta and your baby may fall, and your baby can become distressed. This is why your doctor allows your blood pressure to remain just above the normal range.

Delivery

If you're diagnosed with pre-eclampsia near the end of your pregnancy, your doctor may recommend inducing labour right away. 

If delivery is being considered and your baby is premature (particularly before 32 weeks), you will usually be given 2 steroid injections 12–24 hours apart, which help to mature your baby’s lungs. Whenever possible the birth will be delayed for 24 hours to give the steroids time to be effective. 

If you are still more than a month away from your due date, or if there are signs that your baby may not cope well with a labour, a caesarean section will be recommended as the safest way to deliver your baby.

In general, if you are close to your due date it is possible to have a normal birth after labour is induced. The baby's heart rate will need to be monitored closely once contractions start because the baby is often smaller than usual.

During labour, you may be offered an epidural, which is usually used for pain relief in labour but also helps to keep your blood pressure under control.

You may also be given magnesium sulfate through your vein to prevent seizures. Magnesium also crosses over to your baby and helps protect them.

How is pre-eclampsia monitored?

If you develop pre-eclampsia you will probably be admitted to hospital for close observation. Sometimes you will be given medication to lower your blood pressure, but the aim will be to not lower the blood pressure too much or too suddenly as this can cause distress to your baby.

  • Your blood pressure will be checked about every 4 hours.
  • Blood tests and urine protein levels will be regularly tested to check on your kidney function.
  • You may be offered an ultrasound scan to look at how your baby is growing and to check the blood flow from the placenta to your baby.
  • You may be prescribed medicines to control your blood pressure.

What happens after pregnancy?

Pre-eclampsia always goes away after birth but not immediately. The condition may become more severe for the first few days, so you will need close supervision. This used to be the time when the most serious complications occurred.

This can be a frustrating time for you and your family/whānau because you may be separated from your baby for a few days if you are unwell and your baby is in the neonatal unit.

If you have had severe pre-eclampsia, you may be asked to continue your blood pressure lowering medication and you will be monitored for the first few days after delivery. You may also need to stay in hospital for a few days so that you and your baby can be monitored.  

If you have had severe pre-eclampsia, some hospitals will offer you an appointment to see a specialist a few months after delivery to discuss what has happened and what may happen in future pregnancies.

Learn more

High blood pressure in pregnancy in pregnancy Patient Info, UK
Pre-eclampsia Patient Info, UK
Pre-eclampsia – information for pregnant women Auckland District Health Board, NZ, 2016

Credits: Health Navigator Editorial Team. Reviewed By: Dr J Tuohy, University of Auckland Last reviewed: 07 Oct 2016