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Preeclampsia

A pregnancy-specific multi-system disorder of new-onset hypertension with proteinuria or end-organ damage after 20 weeks, affecting 3 to 8% of women who give birth worldwide1 and a leading cause of maternal-fetal morbidity. Its warning signs are an obstetric emergency. Severe headache, visual changes, upper abdominal pain or sudden swelling in pregnancy require immediate medical evaluation; nutrition supports a healthy pregnancy and recovery, never acute care. Never stop or change blood-pressure medication or low-dose aspirin without talking to your obstetric team, and ask them or a pharmacist before starting any supplement on this page.

Hormonal & Women's Health Evidence-Based

Last updated:

Definition

What Is Preeclampsia?

Preeclampsia is a pregnancy-specific hypertensive disorder defined by new-onset high blood pressure plus either proteinuria or evidence of end-organ damage, arising after 20 weeks gestation in a previously normotensive woman.2

Preeclampsia begins with abnormal placentation. In early pregnancy, the trophoblast cells of the placenta normally remodel the maternal spiral arteries into wide, low-resistance vessels that deliver high blood flow to the developing fetus. In preeclampsia, this remodeling is incomplete. The narrowed vessels under-perfuse the placenta, triggering the release of anti-angiogenic factors (sFlt-⁠1, soluble endoglin) into the maternal circulation. These factors damage the maternal endothelium throughout the body, producing the hypertension, proteinuria, edema and end-organ dysfunction that define the disease.

Preeclampsia is graded by severity and presentation. Each form requires different surveillance and management. The only definitive cure is delivery of the placenta, and close prenatal care is what catches progression early:

Preeclampsia, high blood pressure in pregnancy with the placenta shown, and four warning signs: severe headache, vision changes, upper belly pain and sudden swelling

Gestational Hypertension (precursor)

New-onset blood pressure of 140/90 mmHg or higher after 20 weeks, without proteinuria or end-organ damage. Requires increased monitoring but is not preeclampsia itself.

  • โ†’Primary lever: Weekly BP and urine dipstick checks, plus home BP monitoring
  • โ†’Key supports: Low-dose aspirin3 if it was started early in pregnancy for risk factors, close prenatal monitoring

Preeclampsia without Severe Features

BP 140/90 or higher plus either proteinuria (300 mg or more per 24 hours, or protein/​creatinine ratio ≥ 0.3) or end-organ involvement, without severe-feature criteria. Generally allows expectant management until 37 weeks with intensive surveillance.

  • โ†’Primary lever: Twice-weekly fetal monitoring, weekly labs, daily BP at home, plan delivery by 37 weeks

Preeclampsia with Severe Features / HELLP

BP 160/110 or higher, severe proteinuria, thrombocytopenia (less than 100,000), raised liver enzymes, severe headache, visual changes, pain under the right ribs, pulmonary edema or renal insufficiency4. HELLP (Hemolysis, Elevated Liver enzymes, Low Platelets) is the most severe variant. Requires hospitalization and often immediate delivery.

  • โ†’Primary lever: Hospital admission, IV magnesium sulfate for seizure prophylaxis, antihypertensives, delivery
  • โ†’Key supports: Emergency obstetric care, betamethasone if < 34 weeks, delivery timing per maternal-fetal medicine

Eclampsia & Postpartum Preeclampsia

Eclampsia is the onset of generalized tonic-clonic seizures in a woman with preeclampsia, a true obstetric emergency. Postpartum preeclampsia presents up to 6 weeks after delivery, often catching women off guard once they have gone home. Severe headache and elevated BP postpartum5 must never be dismissed.

  • โ†’Hallmarks: Seizures, altered mental status, postpartum severe headache, BP ≥ 160/110 after birth
  • โ†’Primary lever: Continued BP monitoring 7 to 10 days postpartum, magnesium sulfate if seizing, ER if symptomatic
  • โ†’Key supports: Postpartum BP cuff at home, gradual return to activity, future cardiovascular screening
By the Numbers

Preeclampsia by the Numbers

3 to 8%
of women who give birth worldwide are affected by preeclampsia1
About 42,000
maternal deaths in 2023 from high blood pressure disorders of pregnancy, around 16% of maternal deaths worldwide1
58%
lower risk of eclampsia with magnesium sulfate than placebo, in a trial of more than 10,000 women with preeclampsia6
1.6% vs 4.3%
preterm preeclampsia with low-dose aspirin versus placebo in 1,620 women at high risk (ASPRE trial)3
About 4ร—
later risk of high blood pressure after preeclampsia, with about twice the risk of ischemic heart disease, which is why follow-up matters7
Up to 1 in 6
chance of preeclampsia again after preeclampsia, about 1 in 3 if the baby was born at 28 to 34 weeks8
Signs & Symptoms

Symptoms of Preeclampsia

Early preeclampsia is often silent, so BP and urine checks at every prenatal visit matter. Symptomatic preeclampsia signals severe disease and means being seen immediately8. Know these warning signs by heart.

SymptomWhat happens
Vascular & Cardiovascular Signs
Rapid-Onset Edema (Face, Hands, Pulmonary)Sudden swelling of the face, eyelids and hands (rings stop fitting overnight) is more concerning than gradual ankle swelling. Pulmonary edema (fluid in the lungs) is a severe feature; it causes breathlessness, especially lying flat.
Severe, Persistent HeadacheA new headache that acetaminophen does not relieve, worse than usual or with visual changes, is a severe feature. Frontal or occipital pressure, throbbing or "the worst headache of pregnancy" demands immediate evaluation.
Visual Disturbances (Scotomata, Blurred Vision)Spots or flashing lights, blurred or double vision and temporary loss of vision reflect cerebral edema or retinal vasospasm. These are severe-feature symptoms and require emergency evaluation, even if BP measured at home looks normal.
Shortness of Breath / Pulmonary EdemaNew shortness of breath at rest, when lying flat or with mild activity, especially with chest tightness or pink-tinged sputum, suggests pulmonary edema. Late-pregnancy shortness of breath from a large uterus is common, but new or worsening breathlessness, or breathlessness lying flat, means calling labor and delivery immediately. Call 911 or go to the emergency department for breathlessness at rest or that wakes you and does not settle on sitting up.
End-Organ & Systemic Signs
Right Upper Quadrant or Epigastric PainPain under the right ribs or just below the breastbone, sometimes mistaken for heartburn or gallbladder pain, reflects a swollen, stretched liver and is a severe feature of HELLP syndrome. Most worrying with nausea, vomiting or shoulder-tip pain.
New Nausea / Vomiting in Late PregnancyMorning sickness usually settles by 16 weeks. New nausea and vomiting in the second or third trimester, especially with headache or pain under the right ribs, may signal HELLP syndrome and is not a normal "return of morning sickness."
Decreased Fetal Movement / Slowed Fetal GrowthReduced fetal movements, slowed fetal growth or oligohydramnios on ultrasound reflect placental insufficiency. If your baby is moving less than usual, or the pattern changes, call labor and delivery immediately, even in the night, whatever your blood pressure9.
โš ๏ธ Call labor & delivery immediately if you experience: severe headache that does not improve with rest, vision changes (spots, blurring), severe pain under the right ribs or below the breastbone, sudden swelling of face/hands, shortness of breath, decreased fetal movement or BP 160/110 or higher. Do not wait for your next prenatal visit. Postpartum, these symptoms can appear up to 6 weeks after delivery.
Causes

Causes of Preeclampsia

It is not known exactly what causes preeclampsia10; it begins with the placenta, and several factors raise the risk.

CauseHow It Contributes to PreeclampsiaWhat Helps
How the placenta developsThe placenta's blood supply does not develop fully, releasing factors that damage the lining of blood vessels throughout the body, which is why preeclampsia affects the liver, kidneys, brain and clotting2Low-dose aspirin from 12 weeks until the birth for those at high risk, prescribed by your clinician8; no food or supplement changes how the placenta develops
High blood pressure, kidney disease, diabetes or autoimmune disease before pregnancyEach puts a pregnancy at high risk: chronic high blood pressure, chronic kidney disease, type 1 or type 2 diabetes, and autoimmune disease such as lupus or antiphospholipid syndrome8Aspirin 81 to 150 mg daily from 12 weeks, as your clinician advises118, and keeping the condition itself well treated
Preeclampsia or high blood pressure in a previous pregnancyThis also counts as high risk; after preeclampsia, the chance of it again is up to about 1 in 6, and about 1 in 3 after a birth at 28 to 34 weeks8Aspirin in the next pregnancy, counseling before it after an early birth, and a healthy weight before the next pregnancy, as the diet section supports8
First pregnancy, age, weight, twins and family historyIn the US, a first pregnancy, a BMI over 30, age 35 or older, a mother or sister who had preeclampsia, more than 10 years since the last pregnancy, conceiving through IVF, lower income and being Black are moderate risk factors, and carrying twins or more is a high one11; UK guidance sets the age at 40 and the BMI at 35, and counts twins as moderate8; the NHS adds a South Asian background10Aspirin if more than one moderate factor applies8, and a healthy weight through a balanced diet and exercise, which can help lower the risk10
Low calcium intakeWHO recommends calcium supplements for pregnant women in populations with low dietary calcium intake12, though a 2025 review has made the benefit contested13Calcium-rich foods, and calcium supplements only if your midwife or doctor advises them10
Diagnosis

How Preeclampsia Is Diagnosed

Diagnosis is clinical and lab-supported. Every prenatal visit from 20 weeks should include BP, urine dipstick, weight and symptom screening. Suspected preeclampsia is confirmed with a structured lab workup and fetal evaluation.

TestWhat it shows
At-Home Screening
These do not diagnose preeclampsia, but they identify the women who need urgent clinical evaluation:
Home Blood Pressure MonitoringUse an upper-arm cuff validated for pregnancy. Sit quietly for 5 minutes, feet flat, arm supported at heart level. Take two readings 1 minute apart and average them. Check daily after 20 weeks if at risk; twice daily if BP is borderline. Log every reading with the time. For persistent BP ≥ 140/90, contact your provider or labor & delivery immediately; for any single reading ≥ 160/110, call labor & delivery immediately.
Your Baby's MovementsThere is no set number of movements to count; get to know your baby's usual pattern, and call labor and delivery immediately if movements slow, change or stop, without waiting until the next day9.
Lab & Clinical Tests
Urine Protein QuantificationUrine dipstick at every prenatal visit. Urine protein/​creatinine ratio ≥ 0.3 mg/mg confirms proteinuria. 24-⁠hour urine collection for total protein ≥ 300 mg remains the gold standard. New proteinuria after 20 weeks plus hypertension confirms preeclampsia.
Preeclampsia Lab PanelCBC (platelets < 100,000 is a severe feature), liver function tests (AST/ALT ≥ 2× upper limit), creatinine (≥ 1.1 mg/dL or doubling), uric acid (often elevated), LDH (elevated in hemolysis), peripheral blood smear (schistocytes in HELLP). Repeat weekly or more often once diagnosed.
sFlt-⁠1/PlGF Ratio (where available)A maternal blood biomarker ratio. A ratio ≤ 38 has high negative predictive value, ruling out preeclampsia within 1 week. A ratio > 85 (early-onset) or > 110 (late-onset) supports the diagnosis.
Fetal Ultrasound & Doppler StudiesFetal biometry for growth restriction (estimated fetal weight < 10th percentile). Amniotic fluid index for oligohydramnios. Umbilical artery Doppler for placental resistance (absent or reversed end-diastolic flow is ominous). Uterine artery Doppler in the first trimester helps predict risk.
Preconception Risk ScreeningBefore or in early pregnancy, screen for the risk factors in the Causes table above, using the US thresholds: a BMI over 30 and age 35 or older. One high-risk factor, or more than one moderate-risk factor, justifies low-dose aspirin from 12 weeks until the birth118.
Treatment Comparison

Conventional and Holistic Treatment for Preeclampsia

Preeclampsia needs close obstetric monitoring once diagnosed, and its warning signs and severe features are an emergency. For prevention, low-dose aspirin is the intervention that works and the evidence for nutrition and supplements is limited.

๐ŸŒฟ HOLISTIC
๐Ÿ’Š CONVENTIONAL
๐ŸŒฟ

Holistic / Functional Approach

Prevention-focused: support general and metabolic health in pregnancy, in partnership with OB care

Primary Treatment
Preconception nutrient optimization + adequate protein (80 to 100 g/day) + targeted supplements (calcium, vitamin D, magnesium, choline, omega-⁠3)13 + close prenatal partnership
Duration
Start 3 months before conception, continue through pregnancy and 6 weeks postpartum
Effect on Underlying Disorder
Supports general health in pregnancy; not shown to prevent preeclampsia, apart from calcium where intake is low, which is now contested
Maternal-Fetal Outcome
Depends on early detection and obstetric care

Full Holistic Approach Includes

  • Protein-anchored eating (80 to 100 g daily): eggs, wild fatty fish, pastured poultry, lentils, as part of a balanced pregnancy diet
  • Calcium 1,000 to 1,500 mg/day (food + supplement); WHO recommends 1.5 to 2.0 g of supplemental calcium a day where dietary calcium intake is low12, though a 2025 review has made its effect contested13
  • Vitamin D3 2,000 to 4,000 IU/day with K2, confirmed with your obstetric provider. ACOG notes that an optimal serum level in pregnancy has not been established, so there is no target level to aim at.
  • Magnesium glycinate 300 to 400 mg/day for sleep; NICE advises against magnesium supplements solely to prevent preeclampsia8 (avoid magnesium oxide / citrate at high doses for GI reasons). The top of this range is above the 350 mg/day upper intake level for supplemental magnesium; above that, diarrhea is common. With kidney disease, take it only on your clinician's advice.
  • Choline 450 to 930 mg/day (eggs and fatty fish; not liver, which is high in vitamin A14): supports fetal brain development; its effect on preeclampsia has not been shown
  • Omega-⁠3 DHA/EPA 1 to 2 g/day from low-mercury fatty fish or tested algae oil, for general pregnancy nutrition; NICE advises against fish or algal oils solely to prevent preeclampsia8
  • Daily 30-⁠minute walk, left-side sleep, hydration of about 10 to 13 cups (2.5 to 3 L) a day, stress reduction (gentle yoga, breathwork)
  • Low-dose aspirin 81 to 150 mg/day from 12 weeks until the birth if any high-risk factor (only on OB recommendation)
โš ๏ธ Side effects: Mild GI changes from calcium or magnesium supplements (split doses); rare loose stools from omega-⁠3. Important: Holistic care is supportive, not a substitute for obstetric monitoring. Once preeclampsia is diagnosed, delivery timing and medications must be guided by maternal-fetal medicine.
Supplement Protocol

Evidence-Based Supplements for Preeclampsia

Nothing below should be started without your maternity team's agreement. Always confirm individual doses and any pre-existing-condition modifications with your OB or midwife. The herbs and supplements named as contraindicated in the box after the table should not be used without explicit obstetric approval.

Supplement What it is for Typical range Timing Notes & cautions
High-Quality Prenatal MultivitaminFoundation. Should contain 800 to 1,000 mcg folate (folic acid or methylfolate; folic acid is processed normally with MTHFR variants), 25 to 30 mg iron, 150 mcg iodine, 8 to 12 mg zinc and B vitamins.1 to 2 capsules/day per productWith breakfast or split AM/PMUniversally recommended in pregnancy. Choose third-party tested (NSF, USP).
Calcium Carbonate / CitrateEarlier trials suggested risk reduction in low-calcium diets; a 2025 review has made this contested.13 WHO recommends 1.5 to 2.0 g of elemental calcium a day for pregnant women in populations with low dietary calcium intake12.500 to 1,000 mg a day as a supplement, so food plus supplement reaches about 1,500 mgSplit, 500 mg twice daily; take 2 hours from ironPregnancy-safe. Citrate better absorbed if taking acid-suppressing medication.
Vitamin D3 (with K2)Regulates implantation and immune tolerance. Deficiency (less than 20 ng/mL) is associated with higher preeclampsia risk.2,000 to 4,000 IU D3 + 90 to 180 mcg MK-⁠7 K2 per dayWith a fat-containing meal, morningConfirm the dose with your obstetric provider; the Endocrine Society advises against routine vitamin D blood tests in pregnancy. ACOG notes that an optimal serum level in pregnancy has not been established, so there is no target level to aim at. 4,000 IU/day is the adult tolerable upper intake level and was well tolerated throughout pregnancy in a randomized trial; anything above that needs monitoring, and in pregnancy that means your obstetric team. If you take a blood thinner, clear any vitamin K supplement with the clinician managing it before you start or stop: vitamin K interferes with some anticoagulant medicines, and changing your intake can destabilize your monitoring results.
Magnesium GlycinateMay help sleep. NICE advises against magnesium supplements solely to prevent preeclampsia8.300 to 400 mg elemental magnesium per dayEvening, 30 to 60 minutes before bedPregnancy-safe in glycinate or bisglycinate form. Avoid magnesium oxide / citrate at high doses (laxative effect). The top of this range is above the 350 mg/day upper intake level for supplemental magnesium; above that, diarrhea is common. With kidney disease, take it only on your clinician's advice.
Choline (as bitartrate or phosphatidylcholine)The adequate intake in pregnancy is 450 mg; emerging evidence supports 930 mg/day. Supports fetal brain development; its effect on preeclampsia has not been shown.450 to 930 mg/day (3 eggs supply ~500 mg)With food, split if higher dosePregnancy-safe and underdosed in most prenatals. Eggs and wild salmon are good food sources; avoid liver in pregnancy, which is high in vitamin A14.
Omega-⁠3 DHA/EPA (algae or low-mercury fish oil)Supports fetal brain development; NICE advises against fish or algal oils solely to prevent preeclampsia8. A Cochrane review found omega-⁠3 in pregnancy lowered the risk of preterm birth16.1 to 2 g combined EPA+DHA per day; at least 200 to 300 mg DHAWith mealsChoose third-party-tested low-mercury fish oil or algae oil. Do not use cod liver oil in pregnancy, because of its vitamin A content. In heart trials, fish oil supplements raised the risk of atrial fibrillation, an irregular heartbeat, more so above 1 g a day17, so check this dose with your clinician first. At higher doses fish oil can increase bleeding risk; tell your clinician if you take a blood thinner or have heavy bleeding. Low-dose aspirin taken to prevent preeclampsia also affects bleeding, so mention it too.
Folate (Folic Acid)Supports placentation, methylation and homocysteine regulation.800 to 1,000 mcg/day (often in prenatal)Morning with foodPregnancy-safe and essential. Folic acid or L-methylfolate; folic acid is the form proven to prevent neural tube defects, including in people with MTHFR variants.
Vitamin B12Pairs with folate for methylation; deficient women (especially vegetarian/​vegan) have higher homocysteine and preeclampsia risk.500 to 1,000 mcg/day if levels are lowMorning, sublingual or with foodPregnancy-safe.
Iron (only if deficient)Corrects iron deficiency when a blood test shows it; it is not a treatment for preeclampsia.30 to 60 mg elemental iron/day if ferritin is lowEmpty stomach with vitamin C if toleratedPregnancy-safe when indicated. Take 2 hours from calcium. The top of this range sits above the 45 mg/day tolerable upper intake level for adults. That is appropriate only when correcting a confirmed deficiency under clinical supervision, not as general supplementation. Test ferritin first, and retest rather than staying on it indefinitely.
IodineRequired for fetal thyroid and brain development. Check that your prenatal has 150 mcg, as not all prenatals contain iodine.150 to 250 mcg/day total (prenatal + food)Morning with foodPregnancy-safe at recommended doses. Avoid high-dose kelp or iodine drops without thyroid testing.
Low-Dose Aspirin (81 to 150 mg)Strongest pharmacologic prevention for high-risk women; in the ASPRE trial, preterm preeclampsia fell from 4.3% to 1.6%3. Must be prescribed/​approved by OB.81 to 150 mg/day from 12 weeks until the birthEvening (some evidence of better effect)Only on OB recommendation. Not a self-prescribed supplement; this is a prescription decision.
โš ๏ธ Pregnancy supplement principle: "Pregnancy-safe" does not mean "without input from your provider." Confirm every supplement with your OB or midwife, especially if you have pre-existing conditions, are on medication or have a history of preeclampsia. Many herbs and supplements (vitex, black cohosh, blue cohosh, dong quai, willow bark, high-dose vitamin A) are contraindicated even when sold over the counter.
What to Expect

What to Expect Over Time

Treatment manages preeclampsia until the baby is born, after which symptoms usually improve; diet supports a healthy pregnancy alongside that care, never instead of it10.

Treatment and supportive care, together
First Weeks

A specialist, usually in the hospital, checks how severe it is and agrees on a care plan with more appointments and scans; medicine lowers blood pressure and the risk of stroke, and severe preeclampsia may mean staying in the hospital with medicine to prevent seizures10.

Months 1 to 3

The baby is often safer born early, sometimes before 37 weeks10. After the birth you may need blood-pressure medicine for a few weeks and regular checks, and preeclampsia can still appear up to 6 weeks after birth18.

Months 3 to 12

A postpartum checkup at 6 to 8 weeks follows; before another pregnancy, aim for a healthy weight and after an early birth, ask about counseling on lowering the risk next time8.

Long Term

The later risk of high blood pressure and heart disease is raised, so discuss not smoking, a healthy lifestyle and weight with your doctor8.

When to Seek Care

A severe headache, vision problems such as blurring or flashing lights, severe pain just below the ribs, vomiting or sudden swelling of the face, hands or feet means being seen immediately: call labor and delivery now, during pregnancy or in the weeks after birth8. A seizure is an emergency: call 911 7. Do not wait for your next appointment or try diet first.

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Next Steps

Act at Once on Warning Signs

Your obstetric team manages preeclampsia until the baby is born, and diet supports a healthy pregnancy alongside that care, never instead of it. A severe headache, vision problems or sudden swelling means calling labor and delivery now, even in the weeks after birth. Do not try diet first.

Explore Gestational Diabetes โ†’ Explore High Blood Pressure โ†’

References & Evidence Notes

Each numbered entry below is either a source you can follow or a note setting out what the evidence does and does not support. Both are numbered together so the markers in the text line up.

Last reviewed October 20, 2026. Supplement entries are cross-checked against the NIH National Center for Complementary and Integrative Health and the Linus Pauling Institute Micronutrient Information Center.19 Preeclampsia is a placental disorder and the only definitive treatment is delivery. Nothing on this page treats it. The measure with the strongest preventive evidence is not dietary at all: low-dose aspirin from early pregnancy for women at raised risk, which is guideline-recommended and substantially reduces preterm preeclampsia. Ask whether you qualify. The World Health Organization recommends calcium supplements where dietary calcium intake is low, but a 2025 Cochrane review has made the benefit contested (see the calcium note below), so take calcium only if your midwife or doctor advises it, NHS. Go in immediately for severe or persistent headache, visual disturbance such as flashing lights, pain under the ribs on the right side, sudden swelling of face or hands, vomiting or reduced fetal movements. Those can precede seizures. And low-salt diets do not prevent preeclampsia; restricting salt in pregnancy is unhelpful.

  1. On how common and how serious it is: the World Health Organization's 2025 fact sheet states that preeclampsia affects 3 to 8% of women who give birth worldwide, that high blood pressure disorders of pregnancy caused around 16% of maternal deaths globally, about 42,000 deaths in 2023, and that magnesium sulfate injections reduce the risk of eclampsia by more than half; it recommends low-dose aspirin for women at high risk and calcium supplementation in areas with low dietary calcium intake, WHO, preeclampsia. ↩
  2. On what it is: a pregnancy-specific multisystem disorder of placental origin, defined by new-onset hypertension after 20 weeks with proteinuria or evidence of maternal organ dysfunction. It arises from abnormal placentation with incomplete spiral artery remodeling, producing an anti-angiogenic state and widespread endothelial dysfunction. That mechanism is why it affects liver, kidney, brain and clotting rather than being simply high blood pressure. ↩
  3. On aspirin, which is the intervention that works: low-dose aspirin started between 12 and 16 weeks in women at increased risk substantially reduces preterm preeclampsia; the ASPRE trial reported a large relative reduction, PubMed 28657417, and major obstetric bodies recommend it based on risk factors including previous preeclampsia, chronic hypertension, diabetes, kidney disease, autoimmune disease and multiple pregnancy. If you have any of these, this is the single most useful question to ask at your first prenatal visit. ↩
  4. On warning symptoms and HELLP: severe headache, visual disturbance, right upper quadrant or epigastric pain, vomiting, sudden edema and reduced fetal movements are warning features. HELLP syndrome, with hemolysis, elevated liver enzymes and low platelets, can occur with only modest blood pressure elevation and sometimes without significant proteinuria, which is why symptoms matter as much as numbers. ↩
  5. On afterwards: preeclampsia is associated with a substantially raised long-term risk of cardiovascular disease, hypertension and stroke. It should be treated as a permanent entry in your medical history and a reason for lifelong cardiovascular risk factor attention. Postpartum blood pressure monitoring matters because preeclampsia can present or worsen after delivery. ↩
  6. On management and magnesium sulfate: antihypertensives such as labetalol and nifedipine control blood pressure and reduce stroke risk but do not alter the underlying placental disease. Intravenous magnesium sulfate prevents and treats eclamptic seizures: in the Magpie trial of over 10,000 women, it lowered the risk of eclampsia by 58%, PubMed 12057549. It is also used for fetal neuroprotection in preterm delivery. Delivery of the placenta is the definitive treatment, with timing balancing maternal risk against prematurity. ↩
  7. On eclampsia and later health: the NICHD states that eclampsia, the onset of seizures with preeclampsia, is a medical emergency needing immediate treatment, usually in the hospital, and that women who had preeclampsia are about four times more likely to develop high blood pressure later and twice as likely to develop ischemic heart disease, NICHD, preeclampsia and eclampsia. ↩
  8. On prevention, warning symptoms and afterwards: the NICE guideline on hypertension in pregnancy advises seeing a healthcare professional immediately for a severe headache, vision problems such as blurring or flashing, severe pain just below the ribs, vomiting or sudden swelling of the face, hands or feet; aspirin 75 to 150 mg daily from 12 weeks until the birth for anyone at high risk (previous hypertensive disease in pregnancy, chronic kidney disease, autoimmune disease, diabetes or chronic hypertension) or with more than one moderate risk factor (first pregnancy, age 40 or over, more than 10 years since the last pregnancy, BMI 35 or more, family history, multiple pregnancy); not recommending magnesium, folic acid, vitamins C and E, fish or algal oils, or garlic solely to prevent it, nor salt restriction; and it gives the chance of preeclampsia again after preeclampsia as up to about 1 in 6, about 1 in 3 after a birth at 28 to 34 weeks, with a raised later risk of high blood pressure and cardiovascular disease, NICE NG133. ↩
  9. On your baby's movements: NHS guidance advises calling your midwife or labor and delivery unit immediately, not waiting until the next day, if your baby is moving less than usual, if you cannot feel movements or if the usual pattern changes; it notes that there is no set number of movements and no need to count kicks, NHS, your baby's movements. ↩
  10. On care: NHS guidance states that it is not known what causes preeclampsia; lists its risk factors, including a Black or South Asian ethnic background; states that there is no cure, but treatment lowers blood pressure and stroke risk, severe cases may need a hospital stay and medicine to prevent seizures, the baby is often safer born early, and symptoms usually improve after the birth, though it can develop in the days or weeks after; and advises that aspirin and calcium supplements are taken only when a midwife or doctor advises them, and that a healthy weight through diet and exercise can help lower the risk, NHS, preeclampsia. ↩
  11. On who is at risk, in the US: the US Preventive Services Task Force's 2021 recommendation advises low-dose aspirin (81 mg a day) after 12 weeks of pregnancy for anyone at high risk of preeclampsia, meaning one or more of a history of preeclampsia, twins or more, chronic high blood pressure, type 1 or type 2 diabetes before pregnancy, kidney disease, or autoimmune disease such as lupus or antiphospholipid syndrome; it lists among the moderate risk factors a first pregnancy, a BMI over 30 before pregnancy, a mother or sister who had preeclampsia, age 35 or older, more than 10 years since the last pregnancy, conceiving through IVF, lower income and being Black, which it attributes to environmental, social and historical inequities, not biology; and it reports that ACOG and the Society for Maternal-Fetal Medicine advise starting between 12 and 28 weeks (best before 16) and continuing daily until delivery; they also advise considering aspirin with more than one moderate risk factor, USPSTF, aspirin to prevent preeclampsia (2021). ↩
  12. On calcium: the World Health Organization recommends daily calcium supplementation of 1.5 to 2.0 g of elemental calcium for pregnant women in populations with low dietary calcium intake, to reduce the risk of preeclampsia, as a 2025 review of national guidelines sets out; that review also notes a recent trial finding a lower dose of 500 mg noninferior to 1,500 mg, PMC12728327. ↩
  13. On calcium, where the evidence has genuinely shifted: earlier trials reported that calcium supplementation reduces preeclampsia risk, particularly where dietary calcium is low, and the World Health Organization recommends supplementation in low-intake settings on that basis. A 2025 Cochrane review then re-examined the evidence, excluded nine previously included trials over trustworthiness concerns, and found calcium may make little to no difference to preeclampsia, with baseline calcium intake not affecting that result, PubMed 41330480. This is now a genuinely contested question. If your prenatal care team has recommended calcium, keep taking it and discuss it with them rather than stopping on the strength of this note; adequate dietary calcium in pregnancy is worthwhile regardless. ↩
  14. On liver in pregnancy: NHS guidance lists liver and liver products among foods to avoid in pregnancy, because they contain high levels of vitamin A, which can harm the baby, NHS, foods to avoid in pregnancy. ↩
  15. On salt, and on what does not work: salt restriction does not prevent preeclampsia and is not recommended in pregnancy; plasma volume expansion is part of normal pregnancy physiology. Trials of vitamin C and E supplementation for prevention were negative. Magnesium supplementation does not prevent preeclampsia, though magnesium sulfate is central to treating it, which is a distinction worth keeping clear. ↩
  16. Middleton P, Gomersall JC, Gould JF, Shepherd E, Olsen SF, Makrides M. Omega-⁠3 fatty acid addition during pregnancy. Cochrane Database Syst Rev. 2018;11(11):CD003402. PubMed 30480773. In 70 randomized trials with 19,927 women, omega-⁠3 in pregnancy lowered preterm birth before 37 weeks (risk ratio 0.89) and before 34 weeks (risk ratio 0.58), on high-quality evidence, while probably raising the chance of a pregnancy running past 42 weeks; any effect on preeclampsia itself was uncertain, on low-quality evidence. ↩
  17. Gencer B, Djousse L, Al-Ramady OT, Cook NR, Manson JE, Albert CM. Effect of long-term marine omega-⁠3 fatty acids supplementation on the risk of atrial fibrillation in randomized controlled trials of cardiovascular outcomes: a systematic review and meta-analysis. Circulation. 2021;144(25):1981-⁠1990. PubMed 34612056. Seven trials with 81,210 people followed for about 5 years: omega-⁠3 supplements were linked to a higher risk of atrial fibrillation (hazard ratio 1.25), more so in trials of more than 1 g a day (1.49), and the risk rose with each additional gram. ↩
  18. On preeclampsia after birth: ACOG's patient guidance states that postpartum preeclampsia most often happens within a few days of delivery but can occur up to 6 weeks later, including in women whose blood pressure was normal in pregnancy, and advises calling a doctor immediately for vision changes, a headache that will not go away, shortness of breath, swelling of the face or hands, upper abdominal or shoulder pain, nausea or vomiting, or a reading of 140/90 mmHg or higher, ACOG, conditions after childbirth. ↩
  19. National Center for Complementary and Integrative Health (NIH), nccih.nih.gov, and the Linus Pauling Institute Micronutrient Information Center, lpi.oregonstate.edu/mic. ↩