Preeclampsia: Signs, symptoms, prevention & how to treat

What is preeclampsia?

Preeclampsia is a complication that occurs either during pregnancy, most commonly throughout the second half (after 20 weeks), or soon after delivery. Whilst we don’t know exactly what causes it, it is believed that issues with the development and function of the placenta play a significant role. Preeclampsia affects 5 to 8 in 100 pregnant women in the US [1]. Though preeclampsia is usually mild, it can develop into a very serious illness, and can cause harm to you and the baby if left untreated [2].

How is preeclampsia diagnosed?

Typical preeclampsia symptoms include persistent high blood pressure and high levels of protein in your urine, but there are some other symptoms to watch out for that we’ll go over below.

Blood pressure

Throughout pregnancy, at your regular health checks with your doctor or midwife, your blood pressure will routinely be monitored to check for signs of high blood pressure [3]. A blood pressure test generates two numbers, systolic pressure and diastolic pressure. Blood pressure tests measure the pressure of circulating blood against the artery walls. Systolic pressure is measured during the heartbeat, whereas diastolic is measured between two heartbeats. A blood pressure reading is measured in mmHg, or millimetres of mercury [4].

A typical healthy range for blood pressure is around 120/80mmHg or below–high blood pressure during pregnancy is when your blood pressure reading measures at 140/90mmHg or above in two readings that are 4 or more hours apart [5]. If you typically have a blood pressure reading within a ‘normal’ range and then suddenly develop high blood pressure, you should consult with your doctor right away.

Urine tests

During your routine visits, your care team will also check whether you have high protein levels in your urine with a simple urine test. If the test shows protein in your urine, you may be asked to do another urine sample, which will be sent off to a lab for further testing [3].

Blood tests

If your doctors suspect you may have preeclampsia, they may offer you a blood test to rule it out. The blood test will measure levels of a protein called placental growth factor (PIGF), which is produced by the placenta. PIGF contributes to the growth of new blood vessels. If you have high levels of PIGF, it's likely that you do not have preeclampsia. However, low levels of PIGF may indicate that the placenta is not functioning as it should, which could be an indication that you have the condition. At this point, your care team would refer you for further tests or monitoring [6].

Signs and symptoms of preeclampsia

Preeclampsia symptoms can begin to develop without you noticing. Whilst routine checkups are an effective way to identify early warning signs for this condition, if you do notice any of the symptoms below, particularly after 20 weeks along, it's important to contact your care team right away. Symptoms can include [7]:

• High blood pressure
• Swelling of the face or hands
• A headache that will not go away, even after taking painkillers
• Changes in your vision
• Nausea or vomiting 
• Difficulty breathing
• Sudden weight gain

Can you have preeclampsia without high blood pressure?

Preeclampsia is often defined by protein in your pee and high blood pressure. However, in a very few rare cases, women have had preeclampsia without the high blood pressure feature [8,9]. This would be considered atypical though, and more research is needed to understand how and why this happens.

What can cause preeclampsia?

As mentioned above, the exact cause of preeclampsia is not well understood. However, issues with placental development are thought to underlie the condition. During a typical pregnancy, the placenta develops to link the mom’s blood supply with the fetus’, delivering food and oxygen to the developing baby. 

To ensure that the baby gets enough food and oxygen from the mom, the placenta requires a constant supply of blood. If you have preeclampsia, the placenta doesn’t get enough blood, which means that the energy supply between mom and baby doesn’t work as it should [10]. It is possible that during the first half of the pregnancy the placenta didn’t develop properly, which may contribute to issues with the placenta in later pregnancy. 

Are there any known risk factors for preeclampsia?

There are many factors that may increase the risk of developing preeclampsia. If you have any of the major risk factors below and are trying to conceive or thinking about starting a family soon, we recommend speaking with your healthcare provider.

Major risk factors of preeclampsia

Preeclampsia in a previous pregnancy: If you have had preeclampsia in a previous pregnancy, then you are eight times more likely to develop the condition in another pregnancy [11].

Chronic hypertension: If you experience hypertension, or high blood pressure, outside of pregnancy, you have a higher chance of experiencing preeclampsia during a pregnancy [11]. 

Chronic kidney disease: Kidneys are the body’s filtration system – they filter your blood to remove any waste and help to maintain electrolyte balance and regulate blood pressure [12]. Having chronic kidney disease can reduce kidney functioning, which when added to the extra strain placed on the kidneys during pregnancy, increases the risk of having protein in the urine or high blood pressure. 

Autoimmune conditions: Having certain autoimmune conditions, like Lupus or Antiphospholipid syndrome (APS), may increase the risk of developing preeclampsia during pregnancy [10]. Lupus can increase the risk of developing preeclampsia due to its impact on the functioning of the kidneys. Having APS increases the risk of developing blood clots and other pregnancy complications like preeclampsia. If conditions like lupus and APS are appropriately managed, the risk of developing preeclampsia is reduced. However, if you have one of these conditions, you should speak with your healthcare provider as part of your preconception care.

Other risk factors of preeclampsia

Though not as significant a risk factor for developing preeclampsia as those listed above, women who haven’t previously been pregnant are two times more likely to experience preeclampsia [10]. This is thought to be because the maternal blood system is not yet adapted to the physical demands that a pregnancy places on the body.  Women who have a multiple pregnancy (e.g. twins or triplets) are also more likely to experience preeclampsia. 

Complications arising from preeclampsia

Having preeclampsia increases the risk of pregnancy complications, which can have serious effects on both you and your baby. However, knowing more about preeclampsia and being able to identify any symptoms of the complication in yourself or others, can help you to recognise when to seek extra care. We’ve outlined some of the complications that are more likely if you have preeclampsia.

Fetal growth restriction: Since preeclampsia affects blood flow to the placenta, if not enough blood is able to reach the baby through the placenta, it is possible that the baby will receive less blood and nutrition than is required for sustained fetal growth.

Preterm birth: Depending on the severity of preeclampsia and how far along in the pregnancy you are, you may have a preterm birth, and give birth before 37 weeks. A preterm birth can come with its own set of complications for both the mom and baby. This, in some cases, will be planned in advance to ensure your baby is delivered as safely as possible. If you need to have a planned preterm birth, you may still be able to develop a birth plan and share your wishes for birth, such as who is present, with your care team and partner [13]. 

Hemolysis elevated liver enzymes and low platelet count (HELLP): HELLP is a severe case of preeclampsia which can affect several organ systems, and be life-threatening for both you and your baby. Signs and symptoms of HELLP include headache, upper right belly pain, vomiting and nausea [14]. 

Eclampsia: Eclampsia is a rare but life-threatening condition that occurs in pregnant women with preeclampsia – it results in convulsive seizures or a coma without other causes. Researchers don’t fully know what causes eclampsia, though it may be due to similar risk factors as preeclampsia, issues with blood flow to the placenta, genetic factors or inflammation in the brain [15].

How to prevent preeclampsia

In general, if you’re considered to be at low risk for preeclampsia, one of the best ways to reduce the likelihood of developing the condition is to maintain a healthy lifestyle throughout pregnancy. This can include regular exercise, maintaining a balanced pregnancy diet and other activities which may reduce your blood pressure [16].

If you’re considered to be at a higher risk for developing preeclampsia, your doctor may recommend taking low-dose aspirin from week 12 of pregnancy until you deliver to help reduce your risk. It is thought that aspirin reduces inflammation and increases blood flow to key organs like the kidneys, and the placenta [17].

How is preeclampsia treated?

If you’ve been diagnosed with preeclampsia, it is important to know that in most cases, the only way to cure the condition is by giving birth. However, if you’ve been diagnosed before you’re at full term, your care team will help to manage symptoms and continuously monitor your condition to ensure that your symptoms and blood pressure remain stable. If they have concerns about either yours or your baby’s health and safety, you may be required to stay in hospital, or to deliver the baby early. Below, we've outlined some steps your care team may take to support you and your baby during this time.

Preeclampsia without severe features

If you’ve been diagnosed with preeclampsia without severe features, like seizures, you will be closely monitored by your care team after your diagnosis until you deliver. According to the National Institute of Health and Care Excellence (NICE), if you are experiencing preeclampsia and hypertension, your blood pressure may be monitored every two days, you may have more regular blood tests, and anti-hypertensive medications will be offered [18]. If it is safe to do so, your care team will try to manage symptoms until delivery at 37-38 weeks gestation [19].

Severe preeclampsia

In severe cases of preeclampsia, you may have to be admitted to the hospital for regular monitoring. With severe preeclampsia, you are more likely to develop eclampsia. To prevent eclampsia seizures, you will be given a medication called magnesium sulphate. Depending on the severity of preeclampsia, and whether the preeclampsia has been well managed or not, you may have to be induced earlier than expected [18]. This may seem scary, but your care team will only take this route if medically necessary for you and the baby. 

As things may move quickly, we encourage you and, if you have one, your birthing partner, to speak with your care team and ask any questions you may have about the plan for delivery and next steps. 

What is postpartum preeclampsia?

With most cases of preeclampsia, symptoms will resolve soon after delivery. However, it is possible to have preeclampsia after delivery, most typically within the first 7 days – though the risk remains until about 6 weeks postpartum [20]. If you’ve not had preeclampsia during pregnancy, it is still possible to have postpartum preeclampsia. If you experience any of the following symptoms after birth, it is important that you consult a healthcare provider right away”

Warning signs you may have postpartum preeclampsia [21]

• Blood pressure over 140/90mmHg
• Headache that won’t go away
• Vision changes
• Stomach pain
• Swelling in your hands or feet
• Feeling nauseous or throwing up

If you experience any of the following, you should go to the emergency department to be seen by a healthcare professional right away [21]

• Blood pressure over 160/110mmHg
• Shortness of breath or trouble breathing
• Seeing spots
• Seizure

When to see a doctor

As part of standard antenatal care, you should make sure you go to all of your antenatal appointments. During these visits, your care team will monitor your blood pressure and other potential symptoms or risk factors for developing pregnancy complications like preeclampsia. 

Preeclampsia can be a very serious and, in rare cases, fatal condition if left untreated. It is important that if you have any of the symptoms listed above, you consult with a doctor right away.

If you are experiencing symptoms of preeclampsia throughout pregnancy or after giving birth – Speak with your doctor right away. If you’re experiencing any of the symptoms listed above, or if you’re experiencing any of the following, you should go to the hospital immediately:

• Blood pressure over 160/110mmHg
• Shortness of breath or trouble breathing
• Seeing spots
• Seizure

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