Preeclampsia Warning Signs: Symptoms, Risk Factors, and When to Call for Help

Fact-Checked & Transparent: This article is fact-checked against current CDC, WHO, ACOG, and NHS guidelines. All health information is based on authoritative medical sources. Last verified: June 2026.

⚠️ MEDICAL DISCLAIMER

This article is educational information only. It is NOT a substitute for professional medical advice, diagnosis, or treatment.

Always consult your pediatrician or healthcare provider before making any medical decisions for your baby or child. Every baby is unique, and professional medical guidance is essential.

In case of emergency, call 911 or your local emergency number.

What Is Preeclampsia?

Preeclampsia is a serious pregnancy complication characterised by high blood pressure (hypertension) and signs of damage to other organ systems — most commonly the kidneys, indicated by protein found in the urine. It develops after 20 weeks of pregnancy, almost always in the second half of gestation, and can progress rapidly from mild to severe.

The NHS and the World Health Organization (WHO) estimate that preeclampsia affects around 2–8% of pregnancies globally. In the UK specifically, it affects approximately 6% of pregnancies to some degree. While mild preeclampsia can be monitored and managed, severe preeclampsia and its complications are among the leading causes of serious maternal and fetal illness. Recognising the warning signs early is not an overcaution — it is essential.

The exact cause of preeclampsia is not fully understood, but it is believed to originate in the placenta. In preeclampsia, the placenta does not implant and develop its blood supply correctly in early pregnancy, which later triggers a cascade of effects on the mother's blood vessels and blood pressure. This is why preeclampsia can only be cured by delivery — removing the placenta resolves the underlying process.

Who Is at Higher Risk of Preeclampsia?

Preeclampsia can occur in any pregnancy. However, specific risk factors substantially increase the likelihood. The NHS identifies the following as risk factors:

• First pregnancy: Preeclampsia is significantly more common in women who have not previously carried a pregnancy to term. The risk is lower in second and subsequent pregnancies with the same partner.
• Pre-existing hypertension: Women who have high blood pressure before pregnancy are at higher risk.
• Previous preeclampsia: A history of preeclampsia in a previous pregnancy means a higher chance of it recurring.
• Obesity (BMI over 35 at booking): Obesity is an independent risk factor for hypertensive disorders of pregnancy.
• Multiple pregnancy (twins or more): The larger placental mass involved in multiple pregnancies increases risk.
• Diabetes (type 1, type 2, or gestational diabetes): All forms of diabetes are associated with increased preeclampsia risk.
• Chronic kidney disease: Pre-existing kidney conditions increase susceptibility.
• Autoimmune conditions such as lupus or antiphospholipid syndrome.
• Age 40 or older at first pregnancy.
• Family history of preeclampsia: A mother or sister who had preeclampsia increases your risk.
• A gap of more than 10 years between pregnancies.

Women with two or more of these risk factors are recommended low-dose aspirin (75–150mg daily) from 12 weeks of pregnancy, based on guidance from the NHS and NICE (National Institute for Health and Care Excellence). This intervention has been shown to reduce the risk of preeclampsia developing in high-risk individuals.

Symptoms to Never Ignore

Preeclampsia is sometimes called a "silent" condition because early-stage high blood pressure may cause no perceptible symptoms. This is why blood pressure monitoring at every antenatal appointment matters — it is designed to catch hypertension before symptoms appear.

However, as preeclampsia progresses, characteristic symptoms develop. These should prompt immediate contact with a midwife, GP, or — if severe — attendance at a maternity unit or A&E.

Severe Headache

A headache that does not respond to paracetamol, is unusually severe, feels like pressure behind the eyes, or is described as the "worst headache ever" is a warning sign that blood pressure may be very high. Paracetamol is generally safe in pregnancy; if it provides no relief, seek assessment.

Visual Disturbances

Seeing flashing lights, spots, blurring of vision, or double vision — particularly if these come on suddenly — indicates that high blood pressure is affecting the blood vessels supplying the eyes and potentially the brain. Do not wait to see if this resolves. Go to your maternity unit or call your midwife immediately.

Sudden Severe Swelling

Some swelling of the feet and ankles is common in pregnancy. However, sudden swelling that involves the face and hands — especially swelling that appears rapidly and is more pronounced in the morning — is different in character from normal pregnancy oedema and warrants investigation.

Pain Below the Ribs

A pain or tenderness under the right side of the rib cage can indicate that the liver is being affected by preeclampsia. This can feel like heartburn or indigestion, but it does not respond to antacids and may be accompanied by nausea or vomiting.

Nausea and Vomiting in the Second Half of Pregnancy

Nausea in the first trimester is normal. Significant nausea or vomiting that begins or worsens in the second half of pregnancy — especially alongside any of the other symptoms above — is not normal and may be a sign of preeclampsia progressing.

How Preeclampsia Is Diagnosed

Preeclampsia is diagnosed based on a combination of findings:

Blood pressure readings: A reading of 140/90 mmHg or above on two separate occasions, at least 4 hours apart, after 20 weeks of pregnancy, meets the threshold for gestational hypertension. In the presence of proteinuria or other organ involvement, this becomes preeclampsia.

Proteinuria: Protein in the urine is detected with a urine dipstick at antenatal appointments. If significant proteinuria is found, a more accurate 24-hour urine collection or spot protein-to-creatinine ratio test is arranged.

Blood tests: Blood tests assess kidney function (creatinine, urea), liver function (ALT, AST), and a full blood count to check platelet levels. Abnormalities in these tests indicate which organs are being affected.

Ultrasound: An ultrasound may be arranged to check the baby's growth and the amniotic fluid volume. Preeclampsia can restrict blood flow to the placenta, affecting the baby's growth.

PlGF-based testing: In recent years, a blood test measuring placental growth factor (PlGF) has been introduced in many UK hospitals. A low PlGF level helps identify women at high risk of preeclampsia who may not yet have elevated blood pressure. NICE guidance supports its use in suspected preeclampsia.

Treatment and Management

The only definitive cure for preeclampsia is delivery of the baby and placenta. How quickly this needs to happen depends on the severity of the preeclampsia, the gestational age, and the condition of the baby.

For mild preeclampsia remote from term (before 37 weeks), management involves close monitoring — increased antenatal appointments, blood pressure checks, blood tests, and fetal monitoring. Many women are admitted to hospital for this.

Antihypertensive medication (blood pressure-lowering drugs) is prescribed when blood pressure is persistently high. Labetalol, nifedipine, and methyldopa are the medications most commonly used in pregnancy in the UK. The goal is to reduce the risk of stroke in the mother — antihypertensives do not treat the underlying preeclampsia but prevent its most dangerous acute complication.

Magnesium sulphate is given to women with severe preeclampsia to reduce the risk of eclampsia — seizures caused by very high blood pressure affecting the brain. It is given intravenously, usually during labour and for 24 hours afterwards.

If preeclampsia is severe, or if the pregnancy has reached 37 weeks, induction of labour or a planned caesarean section will typically be recommended. Delivery resolves preeclampsia, though blood pressure can remain elevated for days to weeks postpartum.

HELLP Syndrome

HELLP syndrome is a serious complication that occurs in around 1–2 in 1,000 pregnancies and is considered a severe variant of preeclampsia. HELLP stands for:

• Haemolysis (breakdown of red blood cells)
• Elevated Liver enzymes (indicating liver damage)
• Low Platelets (reducing the blood's ability to clot)

Symptoms of HELLP can include upper abdominal pain (right side), nausea and vomiting, headache, and general malaise. It can develop suddenly and deteriorate quickly. HELLP syndrome requires immediate hospital management and usually delivery. It can occur without all the classic features of preeclampsia being present, which sometimes delays diagnosis.

If you develop sudden severe abdominal pain, right-sided upper pain, or feel very unwell in the second half of pregnancy, go directly to your maternity unit or A&E — do not wait for a scheduled appointment.

After Birth: Monitoring Continues

Preeclampsia does not always resolve immediately after delivery. Blood pressure can remain elevated and in some cases worsen in the first 48–72 hours postpartum. Women who had preeclampsia during pregnancy are closely monitored on the postnatal ward.

NHS guidance recommends that blood pressure medication is continued postpartum if readings remain elevated, and that blood pressure is checked at regular intervals until it normalises. Women are advised to seek urgent help if symptoms return or worsen at home after discharge — postnatal preeclampsia can develop even in women who had no symptoms during pregnancy.

Most women's blood pressure normalises within 6 weeks of delivery. A GP review and blood pressure check at this point is recommended by the NHS.

Long-Term Health After Preeclampsia

Having preeclampsia increases the lifetime risk of cardiovascular disease (CVD), including hypertension, heart disease, and stroke. Research has consistently shown this association. Women who have had preeclampsia — particularly severe or early-onset preeclampsia — should be aware of this long-term risk and prioritise cardiovascular health.

This means: regular blood pressure monitoring (annual checks are reasonable), maintaining a healthy weight, not smoking, keeping active, and eating a balanced diet. These are not dramatic measures, but the evidence supports that lifestyle modification in the years following preeclampsia reduces the long-term cardiovascular risk.

Your GP should record preeclampsia in your medical history. At future health checks, it is worth mentioning your obstetric history so your cardiovascular risk can be assessed appropriately.

Frequently Asked Questions

What is the difference between gestational hypertension and preeclampsia?

Gestational hypertension is elevated blood pressure (140/90 mmHg or above) after 20 weeks without proteinuria or other organ involvement. Preeclampsia is diagnosed when high blood pressure is accompanied by protein in the urine or signs of damage to other organ systems. Gestational hypertension can progress to preeclampsia, which is why close monitoring is important even if initial tests show only raised blood pressure.

Can preeclampsia be prevented?

For women at high risk, low-dose aspirin (75–150mg daily from 12 weeks) significantly reduces the risk of developing preeclampsia, according to NICE guidance. Maintaining a healthy weight before pregnancy and managing pre-existing conditions such as diabetes and hypertension also reduces risk. However, preeclampsia can occur in women with no identifiable risk factors, so routine antenatal monitoring is important for all.

Is it safe to have another baby after preeclampsia?

Yes, many women go on to have further pregnancies after preeclampsia. The risk of it recurring is higher — approximately 1 in 6 women who had preeclampsia in their first pregnancy will have it again, according to the NHS. In a subsequent pregnancy, you should receive early referral to a consultant for specialist monitoring and will likely be offered aspirin from 12 weeks.

What should I do if I have a severe headache and visual disturbances at home?

Do not wait for a scheduled appointment. Call your midwife immediately if during working hours; if after hours, contact the maternity unit directly. If symptoms are severe or you cannot reach anyone quickly, call 999 or go to A&E. Flashing lights combined with headache in the second half of pregnancy is a potentially urgent presentation.

Can preeclampsia affect my baby?

Yes. Severe preeclampsia can restrict blood flow through the placenta, affecting the baby's growth — a condition called fetal growth restriction or intrauterine growth restriction (IUGR). If blood pressure is very high or the pregnancy cannot safely continue, early delivery may be needed, which carries risks of prematurity. With careful monitoring, most babies born to mothers with preeclampsia do well.

I had preeclampsia. Should I tell future doctors even years later?

Yes. A history of preeclampsia is a significant piece of medical history relevant to cardiovascular risk assessment throughout life. Always inform GPs, cardiologists, or any clinician conducting health assessments. It may influence when you are offered blood pressure checks and cardiovascular risk screening.

Key Takeaways

• Preeclampsia is characterised by high blood pressure plus protein in the urine or organ involvement after 20 weeks; it affects approximately 6% of UK pregnancies.
• Key warning signs requiring immediate attention are: severe headache unresponsive to paracetamol, flashing lights or visual disturbances, sudden severe swelling of face or hands, and right-sided pain below the ribs.
• Risk factors include first pregnancy, obesity, pre-existing hypertension, diabetes, multiple pregnancy, and family history — women with two or more risk factors should discuss low-dose aspirin with their midwife.
• HELLP syndrome (haemolysis, elevated liver enzymes, low platelets) is a severe preeclampsia variant requiring emergency care — sudden upper abdominal pain and nausea in late pregnancy warrant urgent hospital assessment.
• The only cure for preeclampsia is delivery; antihypertensive medication and magnesium sulphate manage symptoms and prevent complications in the meantime.
• Preeclampsia increases long-term cardiovascular risk — annual blood pressure monitoring, healthy lifestyle, and informing future doctors of the history are all important ongoing steps.

📋 SOURCES & FACT-CHECKING

This article is compiled and verified against these authoritative sources: - CDC (Centers for Disease Control & Prevention) - WHO (World Health Organization) - ACOG (American College of Obstetricians and Gynecologists) - NHS (National Health Service) - AAP (American Academy of Pediatrics)

Last verified: June 2026

Educational content only. Always consult your pediatrician for medical decisions.

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