Skip to content
BioSignal
Condition

Preeclampsia & Hypertensive Disorders of Pregnancy

Not just high blood pressure in pregnancy — and it does not always end when the baby arrives

Last reviewed
July 2026
Version
1.0
Review cadence
Annually

What it is

The hypertensive disorders of pregnancy are a family, not a single condition, and telling them apart is what determines care. Chronic hypertension is high blood pressure that was present before pregnancy or appears before 20 weeks. Gestational hypertension is new high blood pressure after 20 weeks without the other features. Preeclampsia is a multi-system disorder — it involves the blood vessels, the kidneys, the liver, the blood's clotting cells, the brain and the placenta — and it is not simply hypertension with a pregnancy attached. Preeclampsia with severe features, and eclampsia (preeclampsia with seizures), sit at the severe end. And postpartum preeclampsia can begin, or worsen, after the birth. The definition has moved in a way most people have not heard: preeclampsia no longer requires protein in the urine. The older textbook pairing of high blood pressure plus proteinuria misses cases, so current criteria from ACOG and the ISSHP allow the diagnosis when new hypertension after 20 weeks comes with other evidence of organ involvement — a low platelet count, impaired liver or kidney function, fluid on the lungs, or new neurological or visual symptoms — even when the urine is clear. Waiting for proteinuria is a way to be late.

Why it matters

Preeclampsia is one of the leading causes of serious illness and death for pregnant people and their babies worldwide, and much of that harm is concentrated in delay. It matters here for a reason specific to a page like this one: the condition frequently announces itself through symptoms that sound mundane in isolation — a headache, some swelling, feeling generally awful, seeing spots, pain under the ribs that could be indigestion. Any one of them is common in a normal pregnancy. Together, or on top of a blood pressure nobody has recently measured, they are the presentation of a disease that can go from manageable to dangerous quickly. This page is therefore built so that you do not have to know the word 'preeclampsia' to be pointed toward help — because the readers most at risk are precisely the ones who do not yet suspect it. The other reason it matters is what happens afterwards: the risk does not stop at the delivery room door, and a hypertensive pregnancy is a lasting signal about cardiovascular health that is too often filed away as a thing that happened once.

The evidence

What BioSignal knows about treating this

Guideline-anchored clinical contextLast reviewed July 2026 · reviewed annually · 8 references

What works for Preeclampsia & Hypertensive Disorders of Pregnancy

BioSignal’s clinical summary, most important first.

  1. Low-dose aspirin from early pregnancy for those at higher risk — a preventive measure decided by risk assessment with a clinician, not by self-selection
  2. Antihypertensive treatment — to protect the pregnant person from the consequences of severe hypertension (especially stroke); it treats the blood pressure, not the underlying disease
  3. Magnesium sulfate — to prevent and treat eclamptic seizures in appropriate cases; not a routine treatment for every hypertensive pregnancy
  4. Antenatal corticosteroids where preterm birth is anticipated — for fetal lung maturity, in guideline-defined circumstances
  5. Intensified maternal and fetal monitoring
  6. Delivery — the only definitive resolution of the disease process; its timing is an individualised specialist decision balancing maternal and fetal risk
  7. Postpartum monitoring and blood-pressure follow-up — because the disease can persist or first appear after birth
  8. Long-term cardiovascular risk assessment in the years afterwards
Start Here

New to this? Read these first

  1. FoundationCardiovascular HealthThe best place to understand what actually prevents heart disease.
  2. BiomarkerBlood PressureThe most impactful modifiable vital sign
  3. Body SystemCardiovascularHeart function, blood pressure, and circulatory health.
  4. ConditionHypertensionPersistently elevated blood pressure
Typical Journey

How this usually unfolds

  1. Recognize risk factors
  2. Get diagnosed
  3. Track key biomarkers
  4. Lifestyle first
  5. Evidence-based treatment
  6. Long-term monitoring

An orientation to how this topic is typically approached — not medical advice.

Who is at risk

  • A previous pregnancy affected by preeclampsia — the strongest single predictor
  • Chronic hypertension, or kidney disease
  • Pre-gestational type 1 or type 2 diabetes
  • Autoimmune conditions, particularly antiphospholipid syndrome or lupus
  • Multifetal pregnancy (twins or more)
  • First pregnancy
  • Assisted reproduction
  • Family history of preeclampsia
  • Age over 35, longer interval since a previous pregnancy, obesity
  • NOTE: risk factors are how clinicians decide who benefits from aspirin. They are not a list of things anyone did wrong — preeclampsia is a disease of placental and vascular biology, and it happens to people who did everything right.

How it's diagnosed

Diagnosis is made by a clinical team, and the mechanics matter more than people expect. Blood pressure is the entry point, but a single reading does not make a diagnosis: measurement is easily distorted by the wrong cuff size, a recent walk up the stairs, an arm unsupported or a crossed leg, so the criteria depend on repeated, properly taken, confirmed readings — usually two, at least four hours apart — rather than one number on one occasion. That is also why home readings are a supplement to antenatal care and never a substitute for it. Beyond blood pressure, the assessment looks for organ involvement, because that is what defines the disease: a urine test for protein, a platelet count, liver enzymes, kidney function, and an assessment of symptoms — headache, visual change, upper abdominal pain, breathlessness. Fetal surveillance runs alongside, because the placenta is part of the disease. None of this is a self-assessment, and BioSignal is not going to imply otherwise: the reason to describe it is so that you understand why 'my blood pressure was fine at home' and 'my urine dip was negative' are not, on their own, reassurance.

  • Repeated, properly measured, confirmed blood pressure — not a single reading; cuff size and technique change the number
  • Urine protein — supportive, but its ABSENCE no longer excludes preeclampsia
  • Platelet count — thrombocytopenia is one of the severe features
  • Liver enzymes — transaminase elevation, particularly with upper abdominal pain
  • Serum creatinine — for kidney involvement
  • Assessment of symptoms: headache, visual disturbance, right-upper-quadrant or epigastric pain, breathlessness
  • Fetal assessment — growth, wellbeing and, where relevant, placental blood flow
Most important

Key biomarkers

Blood PressureUrine Albumin-to-Creatinine RatioCreatinine & eGFRALT
Day to day

Lifestyle

  • Go to your antenatal appointments — blood pressure and urine checks at those visits are the screening programme, and they are the reason this is usually caught in time
  • Learn the symptoms that mean 'call today', not 'mention at the next appointment': severe or persistent headache, visual changes, pain under the ribs, sudden swelling of the face or hands, breathlessness, or reduced fetal movement
  • Do not wait to be sure. The people who do well are the ones who called when they were not certain — being wrong about it costs an hour; being late costs more
  • If you have been prescribed aspirin, take it consistently; it is preventive and it works before the disease starts, not after
  • Keep your postpartum appointments and take blood-pressure symptoms seriously in the weeks after birth — this is the period people are most likely to dismiss
  • Years later, tell any new doctor that you had preeclampsia — it is relevant cardiovascular history, not old news
  • Nothing you ate, felt, or failed to do caused this. Preeclampsia is placental and vascular biology, and stress did not bring it on
Explore

Explore this condition across BioSignal

Related Foundations

Cardiovascular Health

Related body systems

CardiovascularBrain

Related conditions

HypertensionStrokeChronic Kidney DiseaseType 2 DiabetesObesityAtherosclerotic Cardiovascular Disease

Frequently asked questions

Does preeclampsia go away as soon as the baby is born?

Not always — and the belief that it does is one of the most dangerous things about this condition, because it makes people stop watching at exactly the wrong moment. Delivery is the definitive treatment for the disease process, which is why it is the endpoint of management. But two things follow that surprise people. First, preeclampsia can persist after birth, and the days immediately afterwards can be when blood pressure peaks — the disease does not switch off with the placenta. Second, and less known: postpartum preeclampsia can appear for the first time AFTER the birth, in someone whose pregnancy was entirely uneventful, typically within the first days to weeks. The symptoms are the same — severe headache, visual changes, pain under the ribs, breathlessness, swelling — and they are easy to attribute to the ordinary exhaustion of new parenthood, which is precisely why they are missed. If you develop those symptoms after giving birth, that is a reason to be assessed urgently, not to wait for the six-week check. And it is a reason not to be reassured by having had a healthy pregnancy.

Is preeclampsia just high blood pressure in pregnancy?

No, and this is why the distinction between the hypertensive disorders matters. Gestational hypertension is new high blood pressure after 20 weeks without other features — it needs monitoring, because some cases progress. Chronic hypertension pre-dates pregnancy or appears before 20 weeks. Preeclampsia is a multi-system disease: it involves the blood vessels, kidneys, liver, platelets, brain and placenta, and the high blood pressure is a manifestation rather than the whole of it. That is why treating the number does not treat the disease — antihypertensives lower the blood pressure, which genuinely protects against stroke, but they do not stop preeclampsia progressing. The other consequence of it being multi-system is the diagnostic one: preeclampsia can be diagnosed without any protein in the urine at all, when new hypertension comes with a low platelet count, impaired liver or kidney function, fluid on the lungs, or new neurological or visual symptoms. The old 'high blood pressure plus protein' rule is out of date, and clinging to it is how cases get missed.

Should I take aspirin to prevent preeclampsia?

That is a question for your maternity team, and the honest answer is 'possibly, if you are in the group it was tested in'. The evidence is real and specific. In the ASPRE trial, women identified by screening as high-risk for preterm preeclampsia were randomised to low-dose aspirin or placebo from early pregnancy: preterm preeclampsia occurred in 1.6% of the aspirin group versus 4.3% of the placebo group — an odds ratio of 0.38. Read both numbers. That is a large relative reduction and an absolute difference of under three percentage points, in a deliberately high-risk, screened population. The USPSTF recommends low-dose aspirin after 12 weeks for people at high risk of preeclampsia, and ACOG guidance is aligned. What none of that licenses is self-prescribing. Whether you are in the risk group is a clinical judgement based on your history, the timing matters (it is started early and works by influencing how the placenta develops — it is preventive, not a treatment once the disease appears), and the dose used in trials is specific. BioSignal will not turn a population-level recommendation into an individual prescription, and 'aspirin is safe in pregnancy' is not a sentence this page is going to write for you. Ask at your booking appointment — that is exactly the conversation the risk assessment exists for.

What symptoms mean I should get help urgently?

These, and you do not need to be sure it is preeclampsia — that is the point. Contact your maternity unit or seek urgent care the same day for: a severe or persistent headache, especially one that does not respond to simple painkillers; visual changes — blurring, flashing lights, seeing spots, or loss of vision; pain below the ribs or in the upper abdomen, particularly on the right (it is often mistaken for indigestion or heartburn); breathlessness; chest pain; sudden or marked swelling of the face, hands or feet, especially with any of the above; feeling suddenly and inexplicably unwell; and reduced or changed fetal movement. A seizure is an emergency — call emergency services. All of these apply after the birth too, for at least the first several weeks. Two things worth saying plainly. Swelling alone is extremely common in normal pregnancy and is not, by itself, a crisis — it is the combination, and the suddenness, that matters. And you are not wasting anyone's time: maternity services would far rather assess you and find nothing than see you late. If you are not sure, call. That is the correct use of this list.

Did I cause this? Was it stress, or my weight, or something I ate?

No. Preeclampsia is a disorder of how the placenta develops and how blood vessels respond to it — biology that is set in motion early in pregnancy, long before symptoms appear, and largely outside anyone's control. It happens to people who exercised, ate well, attended every appointment and did nothing wrong. Some factors do raise risk — a previous affected pregnancy, chronic hypertension, kidney disease, diabetes, autoimmune conditions, twins, first pregnancy, obesity, age — but these are how clinicians decide who might benefit from aspirin, not a list of accusations. It is worth being direct about stress in particular, because it is the one people blame themselves for most: stress is not an established cause of preeclampsia, and a difficult pregnancy does not become your fault because it was also a stressful one. This matters beyond feelings. Self-blame makes people delay calling, minimise symptoms, and apologise for seeking help — which are the exact behaviours that turn a treatable condition into a dangerous one.

Is magnesium sulfate given to everyone with preeclampsia?

No — it is a targeted treatment, and it is worth understanding what it does and does not do. Magnesium sulfate prevents and treats eclamptic seizures. The Magpie Trial, which followed more than 10,000 women, is the evidence: those given magnesium sulfate had a 58% lower risk of eclampsia than those given placebo — in absolute terms, 0.8% versus 1.9%, or about 11 fewer women with eclampsia per 1,000 treated. It is not a small thing, and it is also not a drug without cost: side effects were reported by 24% of women given magnesium versus 5% of those given placebo, most commonly flushing and feeling unwell. That balance is why it is used according to guideline criteria — for preeclampsia with severe features, for eclampsia itself, and in defined circumstances — rather than for every raised blood pressure in pregnancy. It is also not a treatment for the preeclampsia itself: it protects the brain, it does not resolve the disease. The decision about who receives it, when, and for how long is a specialist one.

When will I be delivered?

BioSignal is not going to give you a week, and that is a deliberate refusal rather than an evasion. Delivery is the only definitive resolution of the disease, so the timing decision is a balance between two moving risks: continuing the pregnancy exposes the pregnant person to progression, and delivering early exposes the baby to prematurity. Where that balance sits depends on the gestational age, whether there are severe features, how the blood pressure and blood tests are behaving, how the baby is growing and doing, and how quickly things are changing — and it can change within a day. Guidelines set out the framework, and there are gestational thresholds within which those decisions are made, but applying them is an obstetric judgement about a specific pregnancy on a specific day, made by people who can see the numbers and the scans. A page that named a universal week would be giving medical instruction it is in no position to give, and would be wrong for a meaningful fraction of readers. What this page can tell you is that the question has a real answer, that your team will have a plan, and that it is entirely reasonable to ask them what it is and what would change it.

I had preeclampsia. What does that mean for my health later?

It means you have information about your cardiovascular future that most people do not get until much later — and it is worth using rather than filing away. A systematic review found that after preeclampsia, the relative risk of later hypertension was 3.70 over about 14 years of follow-up, of ischaemic heart disease 2.16 over about 12 years, of stroke 1.81 over about 10 years, and of venous thromboembolism 1.79; overall mortality was raised at 1.49. Two pieces of context keep this honest. These are relative risks in populations, not predictions about you: your absolute risk in the years right after a pregnancy is still low, and the elevated numbers describe a trajectory, not a verdict. And the same review found NO increase in the risk of any cancer, including breast cancer — which is worth stating plainly because it is a fear people carry unnecessarily. The useful reading is that a hypertensive pregnancy is a genuine early signal, in a group that is otherwise young and rarely screened. It is a reason to have blood pressure checked, to have cardiovascular risk factors reviewed, and to tell future clinicians about it — not a reason to be frightened.

Evidence summary

The hypertensive disorders of pregnancy comprise chronic hypertension, gestational hypertension, preeclampsia (including preeclampsia with severe features), eclampsia and postpartum preeclampsia, and distinguishing them determines management. Preeclampsia is a multi-system disorder rather than hypertension in pregnancy: current ACOG (Practice Bulletin 222) and ISSHP criteria permit diagnosis in the absence of proteinuria when new hypertension after 20 weeks is accompanied by thrombocytopenia, renal insufficiency, impaired liver function, pulmonary oedema, or new cerebral or visual symptoms — the older hypertension-plus-proteinuria pairing misses cases. Diagnosis depends on repeated, properly measured, confirmed blood pressure rather than single readings, and on laboratory and fetal assessment; it is not a self-assessment. Prevention with low-dose aspirin is supported for appropriately selected higher-risk patients: in ASPRE, preterm preeclampsia occurred in 1.6% of the aspirin group versus 4.3% of placebo (OR 0.38, 95% CI 0.20-0.74) in a screened high-risk population — a large relative and modest absolute effect — and the USPSTF recommends low-dose aspirin after 12 weeks for those at high risk. That is a population-level recommendation operationalised through clinical risk assessment, not a basis for self-prescription. Antihypertensive therapy protects against the consequences of severe hypertension without altering the underlying disease; the CHAP trial (2,408 participants) found treating mild chronic hypertension in pregnancy reduced the primary composite outcome (30.2% vs 37.0%, adjusted RR 0.82, 95% CI 0.74-0.92) without increasing small-for-gestational-age births (11.2% vs 10.4%, aRR 1.04), addressing a long-standing concern. Magnesium sulfate is a targeted anticonvulsant rather than routine therapy: Magpie (>10,000 women) found a 58% relative reduction in eclampsia (0.8% vs 1.9%; about 11 fewer per 1,000) at the cost of side effects in 24% versus 5%. Delivery is the definitive resolution of the disease process, but timing is an individualised specialist judgement within guideline frameworks and is deliberately not specified here. Risk persists and can first appear postpartum, which is the period most often dismissed. Long term, preeclampsia is associated with later hypertension (RR 3.70), ischaemic heart disease (2.16), stroke (1.81), venous thromboembolism (1.79) and all-cause mortality (1.49), with no increase in cancer risk — relative risks describing a trajectory in a young population rather than individual prediction. Preeclampsia is a disorder of placentation and vascular response and is not caused by stress, diet or behaviour. This page covers hypertensive disorders of pregnancy; chronic hypertension outside pregnancy, gestational diabetes, migraine, routine pregnancy symptoms and general pregnancy care are separate, and BioSignal has not published on pregnancy broadly.

References & sources

  • American College of Obstetricians and Gynecologists. Gestational hypertension and preeclampsia: ACOG Practice Bulletin, Number 222. Obstet Gynecol 2020;135(6):e237-e260 (PMID 32443079; DOI 10.1097/AOG.0000000000003891)
  • Brown MA, Magee LA, Kenny LC, et al. (International Society for the Study of Hypertension in Pregnancy). Hypertensive disorders of pregnancy: ISSHP classification, diagnosis, and management recommendations for international practice. Hypertension 2018;72(1):24-43 (PMID 29899139; DOI 10.1161/HYPERTENSIONAHA.117.10803)
  • Poon LC, Shennan A, Hyett JA, et al. The International Federation of Gynecology and Obstetrics (FIGO) initiative on pre-eclampsia: a pragmatic guide for first-trimester screening and prevention. Int J Gynaecol Obstet 2019;145(Suppl 1):1-33 (PMID 31111484; DOI 10.1002/ijgo.12802)
  • Rolnik DL, Wright D, Poon LC, et al. (ASPRE Trial). Aspirin versus placebo in pregnancies at high risk for preterm preeclampsia. N Engl J Med 2017;377(7):613-622 (PMID 28657417; DOI 10.1056/NEJMoa1704559)
  • US Preventive Services Task Force. Aspirin use to prevent preeclampsia and related morbidity and mortality: US Preventive Services Task Force recommendation statement. JAMA 2021;326(12):1186-1191 (PMID 34581729; DOI 10.1001/jama.2021.14781)
  • Altman D, Carroli G, Duley L, et al. (Magpie Trial Collaborative Group). Do women with pre-eclampsia, and their babies, benefit from magnesium sulphate? The Magpie Trial: a randomised placebo-controlled trial. Lancet 2002;359(9321):1877-1890 (PMID 12057549; DOI 10.1016/s0140-6736(02)08778-0)
  • Tita AT, Szychowski JM, Boggess K, et al. (CHAP Trial). Treatment for mild chronic hypertension during pregnancy. N Engl J Med 2022;386(19):1781-1792 (PMID 35363951; DOI 10.1056/NEJMoa2201295)
  • Bellamy L, Casas JP, Hingorani AD, Williams DJ. Pre-eclampsia and risk of cardiovascular disease and cancer in later life: systematic review and meta-analysis. BMJ 2007;335(7627):974 (PMID 17975258; DOI 10.1136/bmj.39335.385301.BE)

Educational information — not medical advice

Condition pages orient you across the evidence; they don't diagnose or treat. Diagnosis and management belong with a qualified clinician. See our Medical Disclaimer.

Is this condition page clear, accurate, and useful? Your feedback shapes what we review next.

Give feedback