Pre-eclampsia and High Blood Pressure During Pregnancy

Blood pressure is the force that pushes against your blood vessel walls each time your heart squeezes and relaxes to pump the blood through your body.  Blood pressure measurement is a very useful way to monitor the health of your cardiovascular system (heart and blood vessels).

A blood pressure measurement is usually recorded as two numbers, such as 120 over 80 (120/80). High blood pressure is also called hypertension. Hypertension is diagnosed when either the top or the bottom number is higher than normal.

Why is blood pressure important during pregnancy?
During pregnancy, very high blood pressure (severe hypertension) can cause complications for both you and your baby, including:

What are the different types of high blood pressure that affect pregnant women?
1. Chronic hypertension. Chronic, or long-standing, hypertension is high blood pressure that was present before pregnancy or high blood pressure that is diagnosed in the first half of your pregnancy (before 20 weeks). This type of hypertension usually continues after the birth of your baby.  If you have chronic hypertension, you will usually need to take medication throughout your pregnancy. Women with chronic hypertension should discuss any plans for having babies with their doctor prior to conceiving in order to select a safe, effective treatment during conception and pregnancy. Your blood pressure will be monitored regularly during pregnancy and medications adjusted as necessary.  Your baby’s growth can be monitored with ultrasound scans and other tests of well-being.

2. Pregnancy-induced hypertension. Women who develop high blood pressure in the second half of pregnancy without any effects on their kidneys or other organs have ‘pregnancy induced hypertension’ or ‘gestational hypertension’. This condition still requires monitoring in case there is a worsening of blood pressure, or progression to pre-eclampsia.

3. Pre-eclampsia. Pre-eclampsia is a serious condition that only occurs in pregnant women. It begins after 20 weeks gestation and usually takes the form of high blood pressure and abnormal kidney function, but can also involve other organs, such as the liver, blood and brain. Your doctor or midwife can detect pre-eclampsia by measuring your blood pressure and testing your urine for protein (proteinuria). Once pre-eclampsia develops, it does not go away until after the baby is born.  Women with pre-eclampsia may require an earlier delivery, either by labour induction or caesarean section, in order to protect the health of themselves and their baby. In some cases, pre-eclampsia can develop after childbirth and you should alert your doctor or midwife of any concerns you may have after your baby is born.

Pre-eclampsia
Am I at increased risk for pre-eclampsia?
Pre-eclampsia can occur in any pregnancy. About 3–4% of all pregnant women in Australia and New Zealand develop preeclampsia.  You are more likely to develop pre-eclampsia if you:

Women at increased risk of pre-eclampsia may be advised to take low-dose aspirin, with or without calcium, to help reduce the risk. It is important to understand that no medication completely prevents pre-eclampsia, so close monitoring is still required for all women at increased risk.

What are the signs and symptoms of pre-eclampsia?
Most women with pre-eclampsia do not have any symptoms.  Pre-eclampsia is usually detected during a routine antenatal appointment.  However, women with severe pre-eclampsia will have high blood pressure and may experience:

It is very important that you contact your doctor, midwife or maternity hospital if you experience any of these symptoms.  

How is pre-eclampsia treated?
When you are diagnosed with pre-eclampsia, you may be admitted to hospital and have a number of tests including:

While high blood pressure can usually be controlled with medication, the only complete cure for pre-eclampsia is the birth of your baby. The management of pre-eclampsia therefore depends on how far along you are in pregnancy and how seriously you and your baby are affected by the condition.

If you are 37 weeks pregnant or more, your doctor may recommend that you have an earlier-than-planned birth to avoid any decline in your health due to pre-eclampsia.

If you are less than 37 weeks pregnant, you will be regularly monitored to ensure that you are well enough to continue the pregnancy until 37 weeks or more. This may be done on an outpatient basis if you have mild pre-eclampsia, or as an inpatient if your condition is more severe.  

If your blood pressure becomes very difficult to control, your organs are showing signs of worsening damage or there are concerns regarding your baby’s well-being, your doctor may recommend that your baby is born prematurely (before 37 weeks).  Each pregnancy is unique and the exact timing will depend on your own particular situation, including your gestation, your baby’s size, and the severity of your illness. Your doctor may also need to consider transferring you to a larger maternity hospital with facilities to provide advanced care for you and your baby.

What are the potential complications of severe pre-eclampsia?
While the vast majority of women have good outcomes with blood pressure control and timed delivery, some women develop serious complications from pre-eclampsia, including:

Babies may also be affected by:

In settings where resources for antenatal and newborn care are limited, many women and babies die from the consequences of pre-eclampsia or high blood pressure.  While hypertensive disorders may cause or contribute to maternal deaths and stillbirth in Australia and New Zealand, these cases are, fortunately, very rare.

What happens after the birth?
Women with pre-eclampsia usually get better quickly after the birth of their baby; however, complications may still occur within the first few days. You will usually stay in hospital for several days and may need to continue taking medication to lower your blood pressure.  You will be advised about follow-up appointments with your doctor depending on your condition. It is important to attend your 6-week postnatal check up to make sure that your blood pressure has returned to normal and there is no longer any protein in your urine.

If your baby has been born early or is smaller than expected, he or she may need to be cared for in a special care nursery. You will still be encouraged to breastfeed, if you want to. If you are taking medications to lower your blood pressure while breastfeeding, check with your doctor to ensure they are safe to take.

Will I get pre-eclampsia in a future pregnancy?
You may have an increased chance of getting pre-eclampsia again in a future pregnancy. You should be given information about your individual risk and about any additional care that you may need.  Seek specialist advice early in your next pregnancy to plan your antenatal care.