Preeclampsia

Last Update: 07 Apr 2026

Condition

Table of content

1. What is it? 2. Why managing? 3. Non-Medical Options 4. Medications 5. Breastfeeding/ chestfeeding 6. Key Takeaways 7. Limits of Research

Welcome to our Fact Sheet on preeclampsia during pregnancy and lactating. The information is based on current research and may evolve with new scientific knowledge. This content does not replace personalized advice your healthcare professionals.

1. What is preeclampsia?

Preeclampsia is one of the more serious conditions that can develop during pregnancy. It affects about 2 to 8 out of every 100 pregnancies worldwide. It may develop after 20 weeks of pregnancy and happens when your blood pressure is high, and there are signs that your organs or placenta are not working normally.

If preeclampsia is not found and treated in time, it can be dangerous for you and your baby. Preeclampsia can also start for the first time in the days or weeks after birth (postpartum), so warning signs remain important even after delivery.

To diagnose preeclampsia, your healthcare team will first check your blood pressure. If it’s high (140/90 mmHg or higher on two readings about 15 minutes apart), they will look for at least one of the following:

Proteins in your urine, found with a urine test (often called a urine protein or protein–creatinine test)
Signs that organs are under stress, such as changes in blood or urine tests that show your liver, kidneys, brain, heart, or lungs are not working normally
Poor fetal growth, meaning your baby is not growing as expected, usually seen on an ultrasound

What symptoms should I watch for?

Preeclampsia often develops silently, with few or no symptoms at first. This is why regular prenatal visits and blood pressure checks are so important. When symptoms do appear, they may include:

Severe and persistent headaches
Vision changes (blurred vision, seeing spots, light sensitivity, or temporary vision loss)
Sudden or unusual swelling in the hands, feet, face, or legs
Severe pain in the upper right part of the stomach (just below the ribs)
Shortness of breath, sometimes caused by fluid in the lungs
Chest pain or tightness
Nausea or vomiting late in pregnancy.

These warning signs can appear during pregnancy or after birth. If you notice any of them, you should contact your healthcare team or seek urgent care.

Who is more at risk of preeclampsia?

Anyone can develop preeclampsia, even without known risk factors. But your chance may be higher if:

You or a close family member had preeclampsia in a previous pregnancy
this is your first pregnancy
you are pregnant with more than one baby (twins or more)
you have high blood pressure from before pregnancy
you live with obesity, diabetes, kidney disease, or autoimmune conditions like lupus
you became pregnant using fertility treatments (assisted reproduction)
you are age as the risk is higher over age 40
you are persons who self-identify as Black or from another racialized or marginalized community, who may face higher rates of preeclampsia in part because of more health and social inequalities.

Having one or more of these does not mean you will develop preeclampsia; It simply means your healthcare team may follow you more closely.

With regular prenatal care, preeclampsia can often be found early. With timely care and treatment, preeclampsia can be managed safely with good outcomes for you and your baby.

2. Why is it important to manage preeclampsia during pregnancy?

Preeclampsia is closely linked to problems with the placenta. The placenta is the organ that brings oxygen and nutrients from your blood to your baby. When the placenta does not work properly less blood may reach your baby which can interfere with getting enough oxygen and nutrients

Over time, this can lead to:

slower growth or low birth weight
less amniotic fluid
preterm birth (birth before 37 weeks)

In very severe cases, preeclampsia can lead to eclampsia, a dangerous complication that causes seizures for the pregnant person.

Getting regular monitoring and timely treatment can reduce these risks and help support good outcomes for you and your baby.

Understanding Pregnancy Risks

Complications like miscarriage (loss of the baby), congenital malformations (birth defects), preterm birth (birth before 37 weeks), or other health problems can happen in any pregnancy for many reasons. This is called the background risk. Research helps estimate how preeclampsia may increase these risks, but it is important to remember:

Some risks are well studied, while others still need more research.
Your personal risk depends on many factors, including your age, medical history, genetics, ethnicity, lifestyle (such as smoking or alcohol use), and other health conditions.

A lot of research has been done on preeclampsia. According to studies, when preeclampsia is not well monitored or treated, it can:

Increase the risk of seizures (eclampsia), stroke, heart problems, liver problems, serious bleeding (hemorrhage), and damage to the organs for the pregnant persons
Lead to complications such as placental abruption (the placenta separating too early) and perinatal death (death before, during, or just after birth – this is rare but serious)
Increase the chance of needing a cesarean delivery
Reduce blood flow to the baby, causing slowed growth or low birth weight
Raise the risk of preterm birth or stillbirth (this remain uncommon but is more likely when preeclampsia is not well controlled)

Preeclampsia can also affect health after pregnancy. People who had preeclampsia have a higher risk of high blood pressure and heart disease later in life, so a follow-up with a primary care provider after pregnancy (BP checks, lifestyle, etc.) is recommended.

The table below summarizes what research has found about the risks associated with unmanaged or not well-control preeclampsia during pregnancy compared to the usual background risks.

Table 2. Possible risks of unmanaged preeclampsia during pregnancy.

Who?	What?	What does research say?
Pregnant person	Eclampsia	Rare but serious complication of preeclampsia that causes seizures and can be life-threatening without urgent care.
	Cesarean delivery	Higher chance of needing a cesarean delivery.
	Placental abruption	Increased risk of the placenta detaching from the uterus before birth, which can cause heavy bleeding and put the baby at risk.
	Organ and blood problems	Higher risk of damage to the kidneys and liver (including a rare (1% of cases) but serious condition called HELLP syndrome), as well as problems with the brain and blood-clotting system.
	Long-term health after pregnancy	Higher risk of high blood pressure and heart and blood vessel disease later in life, so long-term follow-up is recommended.
Unborn baby	Congenital malformations	High blood pressure late in pregnancy is not a risk factor for malformation.
	Premature birth	Higher chance of being born preterm (before 37 weeks) compared with pregnancies without preeclampsia.
	Low birth weight	Increased risk of low birth weight (less than 5 pounds and 8 ounces [2,500g]) or baby being smaller than expected for gestational age.
	Neonatal health	Higher chance of needing care in a neonatal unit and help with breathing after birth.
	Stillbirth	Higher risk that the baby dies before or during birth compared with pregnancies without preeclampsia. This remains rare but is more likely when preeclampsia is not well controlled.
Future child	Brain development	Some studies found a small increase in learning or behaviour difficulties in children exposed to preeclampsia in pregnancy, but results are mixed and most children do well. We need more research to confirm.
Future child	Long-term health issues	Some studies have shown a higher risk of high blood pressure or heart and blood vessel problems later in life for children exposed to preeclampsia during pregnancy. These increases are usually small, and more research is needed.

*These are general patterns seen in research studies looking at many pregnancies. They do not predict what will happen in any one pregnancy.

3. What can I do to manage preeclampsia other than medications?

Managing preeclampsia involves more than just medications. Here are steps you can do, with the guidance of your healthcare team, to support your health:

Follow your care plan: Go to all prenatal appointments so your blood pressure and your baby’s growth can be closely monitored.
Watch your symptoms: Tell your healthcare team right away if you notice severe headaches, vision changes, sudden swelling, chest pain, shortness of breath, or pain in the upper right side of your belly.
Check your blood pressure at home (if advised): If your team has asked you to, use a home blood pressure monitor and write down your numbers. Bring your readings to your appointments or share them as directed.
Follow advice about rest and activity: Your healthcare team will tell you whether you should reduce your activities, stay home from work, or avoid exercise.
Support your well-being: Techniques like deep breathing, relaxation, listening to music, or talking with someone you trust can help with stress and coping, even though they do not treat preeclampsia itself.

These steps do not replace medical care, but combining them with regular monitoring and the treatments recommended by your healthcare team can help manage preeclampsia during pregnancy.

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4. Medications prescribed for managing preeclampsia

If you’re at a higher risk of developing preeclampsia or have been diagnosed with it, your healthcare team may prescribe medications to lower risks for you and your baby. These medicines help control blood pressure, prevent seizures, and reduce complications. Sometimes, this can also allow the pregnancy to continue a bit longer, when it is safe to do so. Not everyone with preeclampsia will need all of these treatments.

What does research say?

Before delivery, your healthcare provider may prescribe medications to lower your blood pressure and reduce the risk of complications. Common antihypertensive (blood pressure) medications include:

Labetalol
Nifedipine
Methyldopa
Hydralazine (most often used in hospital, by IV, when blood pressure is very high)

Based on Canadian and international guidelines and studies, these medicines are commonly used in pregnancy when needed. They have not been shown to increase the chance risk of malformations above the usual background risk; uncontrolled high blood pressure itself is considered more harmful for you and your baby than these treatments.

In hospital, your healthcare team may also use other medicines like magnesium sulfate to prevent or treat seizures (eclampsia), corticosteroids if an early birth is expected to help your baby’s lungs mature or, in rare case, platelet transfusion (or other blood products) if your platelet levels are very low or you have serious bleeding.

Some medications may be started before or early in pregnancy to lower the chance of developing preeclampsia in people who are at higher risk. These should always be discussed with a healthcare provider before starting.

Low-dose aspirin (81 or 162 mg/day): Often recommended at night in early pregnancy, usually before 16 weeks of gestation and stopped around 36 weeks. Research as shown it can help prevent preeclampsia in people at high risk of developing it.
Calcium supplements (at least 500 mg/day): Suggested for people with a low dietary intake of calcium (less than 900 mg per day). As a guide, 1 cup (250 mL) of milk, fortified plant-based milk, or yogurt gives about 300 mg of calcium, while ¼ cup of almonds gives about 90 mg.

It’s important to always talk with your healthcare provider before starting, stopping, or changing any medication during pregnancy.

Table 3. Some medications that can be prescribed in Canada for preeclampsia

Medication Types	Medication Names	Brand names
Antihypertensives	Labetalol	e.g. Trandate®
	Nifedipine	e.g. Adalat®, Adalat XL®
	Hydralazine	e.g. Apresoline®
	Methyldopa	e.g. Aldomet®
Seizure Prevention	Magnesium Sulfate	Hospital use only (no brand)
Prevention	Low-dose aspirin	Generic low-dose aspirin
Prevention	Calcium supplement	Various over-the-counter brands

How do I know which medication to take?

Each medication has its risks and benefits. Your healthcare team is best equipped to guide you in making an informed decision adapted to your personal needs. They will work closely with you to find the safest options for managing preeclampsia and protecting both you and your baby.

Always discuss any changes in your medication intake with your healthcare team (pharmacist, nurse, doctor).

5. Can preeclampsia or its treatment affect breastfeeding or milk supply (lactation)?

Most people who have preeclampsia can breastfeed or chestfeed safely if they choose to. Lactation is not harmful after preeclampsia. Some studies suggest that it may even bring extra health benefits like to help lower your future risk of high blood pressure and heart disease.

If you need medication to manage high blood pressure during pregnancy or after birth, this usually does not mean you must stop lactating. Common blood pressure medicines such as labetalol and nifedipine pass into breastmilk in very small amounts and are generally considered compatible with breastfeeding or chestfeeding when prescribed by your healthcare provider.

If you need medication to manage preeclampsia during pregnancy or after birth, most of these medicines are considered safe while lactating because only very small amounts pass into breast milk. In some cases, your healthcare provider may adjust your prescription to make sure it is the best option for you and your baby.

Some people who experienced severe preeclampsia or complications (for example, ICU stay, major blood loss, or very early birth) may need more time to recover after delivery. This can sometimes delay lactation or make it more challenging. Support from your care team can make a big difference.

If you have any concerns or questions, talk to your healthcare professional (doctor, nurse, pharmacist) or a lactation consultant from your region (e.g. Canadian Lactation Consultant Association).

Key Takeaways

Preeclampsia is a serious condition that usually develops after 20 weeks and involves high blood pressure and possible organ problems. Sometimes, it can start for the first time in the days or weeks after birth (postpartum).
Preeclampsia can increase the risks of complications like preterm birth, low birth weight, or, in severe cases, seizures (eclampsia) and long-term health problems for the pregnant person.
Medications like low-dose aspirin is recommended to prevent preeclampsia for people at higher risk of preeclampsia.
Prescribed antihypertensives such as labetalol are commonly used to manage preeclampsia and lower the risk of complications.
Lactating is possible for people who had or have preeclampsia even if medication is needed.
Always talk to your healthcare provider before starting, stopping, or changing any treatment.
While preeclampsia can be scary, with close monitoring it is still possible to have a pregnancy with good outcomes and a healthy baby.

Research Is Great, But It Is Not Perfect

Making informed health decisions also means understanding what research knows and what it cannot say. Here’s what our group of experts found about the limits of research on preeclampsia research during pregnancy:

Conflicting results: Most studies looking at neurodevelopmental outcomes on the baby don’t differentiate what’s caused by preterm birth or fetal weight from what’s actually caused by preeclampsia.
A complex condition: Preeclampsia can look different for each person. It may start earlier or later in pregnancy and have different causes, which makes it harder to study.
Timing matters: Early-onset (before 34 weeks), late-onset (after 34 weeks) and even postpartum preeclampsia have different risks, but many studies group them together.

More research is needed, especially larger and more diverse studies to better understand long-term health for both parents and children.

References

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