Pre-eclampsia: The Warning Signs Every Pregnant Woman Should Know

TL;DR: Pre-eclampsia is a condition that causes high blood pressure in pregnancy, usually from 20 weeks, and it can also appear in the days or weeks after birth. Warning signs include a severe headache that will not go away, blurred or flashing vision, pain just below the ribs, and sudden swelling of the face, hands or feet. Black women, women in a first pregnancy and women with high blood pressure are at higher risk. If you notice these signs, contact your midwife, maternity unit or hospital straight away.

You go to antenatal clinic, wait your turn on the bench, and a nurse wraps a cuff around your arm and asks you for a urine sample. It can feel like routine, the part of the visit you rush through to get to the scan or the doctor. But those two small checks are looking for one of the most serious conditions in pregnancy. Pre-eclampsia often starts quietly, with no symptoms you can feel, and then it can move fast. Knowing the warning signs, and knowing they are worth acting on the same day, can protect you and your baby.

What is pre-eclampsia?

Pre-eclampsia is a pregnancy-related condition that causes high blood pressure, and it usually develops from 20 weeks of pregnancy onwards, according to the NHS. It can also start in the days or weeks after your baby is born. Beyond raised blood pressure, it is a sign that organs such as the kidneys and liver are under strain, which is why protein can show up in your urine.

The World Health Organization estimates that pre-eclampsia affects 3 to 8 percent of women who give birth worldwide, and that hypertensive disorders of pregnancy cause about 16 percent of maternal deaths globally. Left untreated, it can lead to eclampsia, which means seizures, and to stroke and other serious problems for both mother and baby.

Why this matters so much in Africa

The burden falls heavily on African women. A systematic review of 82 studies across 24 African countries found that about one in 10 pregnancies in Africa are affected by a hypertensive disorder, with pre-eclampsia making up a large share. The authors also flagged a high rate of severe forms, which carry the greatest risk to mothers and babies, and found rates were higher in Central and Western Africa.

Part of the gap is access. The WHO notes that magnesium sulfate, the medicine that more than halves the risk of eclampsia, is still limited in many low-resource settings. That makes early detection at antenatal visits, whether you are in Lagos, Kumasi, Nairobi or Johannesburg, even more important. We look at the wider picture in why Black women face higher risks in pregnancy and childbirth.

Who is most at risk of pre-eclampsia?

Any pregnant woman can develop pre-eclampsia, but some face a higher chance. The NHS lists these risk factors:

• being pregnant for the first time, or being 40 or older
• having high blood pressure, diabetes or kidney disease before pregnancy
• being of Black or South Asian ethnicity
• carrying twins or more
• a family history of pre-eclampsia
• a BMI of 35 or more before pregnancy
• more than 10 years since your last pregnancy

Having pre-eclampsia or high blood pressure in a previous pregnancy also raises your risk, and UK guidance from NICE counts it as a high-risk factor, along with chronic kidney disease, autoimmune conditions such as lupus, and type 1 or type 2 diabetes. If any of these apply to you, say so at your booking appointment, even if nobody asks.

What are the warning signs of pre-eclampsia?

The early signs, high blood pressure and protein in the urine, are often silent, which is why clinic checks matter. When symptoms do appear, the NHS says to look out for:

• a severe headache that does not go away with simple painkillers
• problems with your vision, such as blurred vision or seeing flashing lights
• pain just below your ribs
• feeling very unwell
• sudden swelling of your face, hands or feet
• vomiting, or heartburn that does not get better with antacids

Some swelling of the feet and ankles is common in late pregnancy, especially in the heat or at the end of a long day. The difference to watch for is swelling that comes on suddenly, or swelling in your face and hands. A headache that paracetamol does not touch, or vision that suddenly goes strange, is not something to sleep off.

Why do blood pressure and urine checks matter at every visit?

Because pre-eclampsia often has no symptoms at first, measuring your blood pressure and testing your urine for protein at each antenatal visit is how it is usually caught early. A rising reading can be the first and only clue. If your clinic skips a check, or you are not told your numbers, you can ask: "What was my blood pressure today, and is that normal for me?" Our guide to questions to ask at every antenatal appointment has more prompts, and prenatal tests and scans explains what each routine check is for.

It helps to know your baseline. A blood pressure taken early in pregnancy gives your clinician something to compare later readings against.

Can low-dose aspirin help prevent pre-eclampsia?

Yes, for women at higher risk, a daily low dose of aspirin started early in pregnancy lowers the chance of developing pre-eclampsia. It is a prescribed treatment, so only take it if a clinician advises it.

The guidance differs a little by country. In the UK, NICE advises women at high risk, or with more than one moderate risk factor, to take 75 mg to 150 mg of aspirin daily from 12 weeks until the baby is born. In the US, ACOG recommends 81 mg a day for women at high risk, started between 12 and 28 weeks, ideally before 16 weeks, and continued until delivery. The WHO recommends low-dose aspirin by 20 weeks or when antenatal care begins, plus calcium supplements in settings where people get little calcium from their diet.

If you have risk factors and nobody has mentioned aspirin, it is fair to ask about it at your first antenatal visit. Timing matters, so earlier is better.

Can pre-eclampsia happen after the baby is born?

Yes. Postpartum pre-eclampsia can develop even if your blood pressure was normal throughout pregnancy. ACOG explains that it most often happens within a few days of delivery, but it can occur up to six weeks later, and if untreated it can cause stroke and seizures.

This is easy to miss. You are home, exhausted, and every headache feels like lack of sleep. But the same warning signs apply after birth: a headache that will not go away, vision changes, pain in the upper right side of your belly, swelling of the face or hands, or shortness of breath. Make sure whoever is helping you at home, your partner, your mother, your sister, knows them too. The weeks after birth bring other changes worth watching, which we cover in our postpartum depression guide.

When to act, and how fast

Do not wait for your next appointment. If you have any of the warning signs above, during pregnancy or after birth, contact your midwife or maternity unit straight away. In the UK, the NHS says to call 111 if you have recently given birth or cannot reach your maternity unit, and 999 is the number for any emergency. Wherever you live, if you have a severe headache with vision changes, a seizure, chest pain or trouble breathing, call your local emergency number or get to hospital immediately. Going in and being told everything is fine is always a better outcome than staying home.

Pre-eclampsia also matters for your long-term health. Women who have had it face a higher risk of stroke later in life, which we explain in stroke in women: the signs that get missed.

This post is education, not medical advice. Your midwife, doctor or obstetrician knows your history and can tell you what your readings mean.

Keeping your own record helps. Asele lets you log symptoms such as headaches, swelling and how you are feeling each day, and the Asele Health Brief turns your logs into a pre-visit summary you can show your clinician. If you want to talk through what a symptom might mean or what to ask at clinic, Amara can help in Yoruba, Hausa, Igbo, Swahili, French or English. You can find us at Asele.

References

1. NHS. Pre-eclampsia. nhs.uk
2. World Health Organization. Pre-eclampsia fact sheet. who.int
3. Noubiap JJ, et al. The burden of hypertensive disorders of pregnancy in Africa: a systematic review and meta-analysis. Journal of Clinical Hypertension, 2019. pmc.ncbi.nlm.nih.gov
4. NICE. Hypertension in pregnancy: diagnosis and management (NG133). nice.org.uk
5. ACOG. Low-Dose Aspirin Use During Pregnancy, Committee Opinion 743. acog.org
6. ACOG. 3 Conditions to Watch for After Childbirth. acog.org