Understanding Preeclampsia: How Low-Dose Aspirin May Help Protect Your Pregnancy

You may come across the word preeclampsia during pregnancy — at a clinic, in a prenatal class, or while scrolling online, and it’s normal to wonder what it means. In simple terms, preeclampsia is a pregnancy condition linked to high blood pressure that healthcare providers watch for throughout pregnancy (and sometimes after birth). It can often be found early through routine checks, and there are clear next steps if concerns come up.

Learning about preeclampsia — what it is, the symptoms to keep in mind, and what prevention options exist—can help you feel more informed and prepared during pregnancy.

What Is Preeclampsia?

Preeclampsia is a condition that can develop during pregnancy, usually after 20 weeks or sometimes up to six weeks after birth (known as postpartum preeclampsia). It happens when a pregnant or postpartum person has high blood pressure (140/90 mmHg or higher) and signs that the placenta or other organs may be under strain.

Preeclampsia affects about 2–8% of pregnancies worldwide. We don’t fully understand why it happens, but the placenta seems to play a key role. Problems with the placenta may affect blood flow, which can slow the baby’s growth and increase the chance of early birth.

Most cases are mild and manageable with close monitoring and medication. In some cases, preeclampsia can become serious and lead to complications such as seizures (eclampsia), stroke, or organ damage. With regular prenatal care, healthcare teams work to catch signs early and reduce these risks.

What Should You Watch For?

Preeclampsia may have no symptoms at first, which is why your healthcare provider checks your blood pressure at each visit (and may test your urine) to catch early signs. Many pharmacies also offer quick blood pressure checks between appointments. If your reading is higher than expected, or you’re unsure what it means, your healthcare provider can help.

You should also contact your healthcare provider if you notice any of these warning signs:

• Severe or ongoing headache

• Vision changes (blurred vision, flashing lights or spots)

• Sudden swelling of the face or hands

• ·Severe pain in the upper belly, just below your ribs

• Shortness of breath or chest pain

• Nausea or vomiting late in pregnancy

• Feeling suddenly very unwell

Seek emergency care right away if symptoms are severe, you have a seizure, or your blood pressure is 160/110 or higher.

These symptoms can happen during pregnancy or in the first few weeks after birth. Trust your instincts — if something feels off, it's always better to call your healthcare provider or get checked.

Can Preeclampsia Be Prevented?

For people at higher risk, such as those with a history of preeclampsia, chronic high blood pressure, certain medical conditions (kidney disease, diabetes, autoimmune conditions), or a twin/multiple pregnancy, the most evidence-based prevention option is low-dose aspirin. It is not recommended for everyone, so the decision should always be made with your healthcare provider.

Research shows that low-dose aspirin can improve blood flow to the placenta and lower the risk of developing preeclampsia, especially when started before 16 weeks of pregnancy.

The Society of Obstetricians and Gynaecologists of Canada (SOGC) recommends:

·         81 to 162 mg once daily (one to two baby aspirins)

·         Taken at bedtime

·         Usually stopped around 36 weeks

Low-dose aspirin has been widely studied and is considered compatible with pregnancy when taken as recommended. Studies have not shown an increased risk of birth defects. It may slightly increase bleeding risk, but for people at high risk, the benefits usually outweigh the risks.

What You Can Do

• Talk early with your healthcare provider about your risk and whether low-dose aspirin is right for you (don't start or stop on your own)

• Attend all prenatal appointments as recommended by your care team

• Learn the warning signs and seek care if they appear

• Take medications exactly as prescribed

Remember, preeclampsia can also happen after delivery, so continue to watch for symptoms even after your baby is born.

If preeclampsia is a concern, you’re not alone and your healthcare team has clear ways to monitor and manage it. Knowing the signs and attending prenatal visits can make a real difference.

Want to learn more?

Visit healthypregnancyhub.ca for evidence-based, accessible information you can trust, written and reviewed by experts with Canadian parents in mind.

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This article is based on the 2022 Society of Obstetricians and Gynaecologists of Canada (SOGC) Clinical Practice Guideline and Hypertension Canada recommendations. Always consult with your healthcare provider about your individual situation.