SWARAJ HOSPITAL & RESEARCH INSTITUTE

BOLANGIR, ODISHA  •  OBSTETRICS & GYNAECOLOGY CLINICAL PATHWAY SERIES

Clinician Reference Infographic

Pre-eclampsia: Prediction and Prevention

Pre-eclampsia is a major cause of maternal and newborn harm, and part of it can be predicted and prevented. This guide covers risk stratification, screening tests, aspirin and calcium, monitoring, and counselling, using the SCREEN approach.

🎯 AT A GLANCE — PRE-ECLAMPSIA PREDICTION AND PREVENTION

Pre-eclampsia is new high blood pressure (140/90 mmHg or more) after 20 weeks with protein in the urine or organ damage; it affects about 2–8% of pregnancies and is a leading cause of maternal and fetal illness and death

Prediction starts with the clinical history: high-risk and moderate-risk factors identify women who need prevention without any special test

Combined first-trimester screening (history, mean arterial pressure, uterine artery Doppler, and placental growth factor) can detect most preterm pre-eclampsia where available

Low-dose aspirin from 12 weeks (before 16) cuts the risk of preterm pre-eclampsia in high-risk women; calcium helps where dietary intake is low

Blood tests such as the sFlt-1 to placental growth factor ratio help to rule out or confirm disease in women with symptoms, not to screen well women

Pre-eclampsia can appear without warning, so check BP and urine at every antenatal visit and teach every woman the danger signs

🚨 ACT NOW IF

BP of 160/110 mmHg or more — severe: give antihypertensive treatment within 30–60 minutes, magnesium sulfate, and refer

Severe headache, visual disturbance, upper abdominal pain, vomiting, or sudden swelling — assess for pre-eclampsia the same day

Convulsions — eclampsia: airway, left side, magnesium sulfate, and delivery after stabilisation

Breathlessness, reduced urine, or low platelets or abnormal liver tests — severe features or HELLP syndrome (haemolysis, elevated liver enzymes, low platelets)

Reduced fetal movements or poor growth — same-day cardiotocography and ultrasound

🗺️ THE PATHWAY AT A GLANCE

1 · BookingRisk assessment from the history; baseline BP, urine protein, weight, and tests

2 · 11–14 weeksCombined screening where available; start aspirin if high risk

3 · 12–16 weeksAspirin 75–150 mg nightly; calcium if intake is low

4 · 20–24 weeksUterine artery Doppler in selected women

5 · Every visitBP, urine, symptoms, fetal growth from 28 weeks

6 · After birthBP check at days 3–6, and long-term cardiovascular follow-up

STEP 1 · PREDICT FROM RISK FACTORS — who needs prevention

🔎 RISK STRATIFICATION

Topic	Details
Rule	One high-risk factor, or two or more moderate-risk factors means offer low-dose aspirin (NICE, ACOG, and FIGO use a similar approach)
High-risk factors	Previous pre-eclampsia or hypertension in pregnancy, chronic hypertension, diabetes before pregnancy, chronic kidney disease, autoimmune disease (lupus, antiphospholipid syndrome), and multiple pregnancy
Moderate-risk factors	First pregnancy, age 40 or over, body mass index above 30–35, family history of pre-eclampsia, interval above 10 years since the last birth; some guidelines add IVF, low income, and previous small baby, abruption, or stillbirth
Why	The history alone catches about a third to half of cases; adding scans and blood tests improves detection

STEP 2 · PREDICT WITH TESTS — where available

🧪 SCREENING TESTS

Test	What it adds
Combined first-trimester screening (11–13+6 weeks)	Maternal history, mean arterial pressure, uterine artery pulsatility index, and placental growth factor, combined in a validated algorithm (Fetal Medicine Foundation model); about 75–90% of preterm pre-eclampsia is found at a 10% false-positive rate (varies between studies)
Mean arterial pressure	Measured with a validated device, seated, in both arms; higher values early in pregnancy increase risk
Uterine artery Doppler	At 11–14 weeks (as part of combined screening) or 20–24 weeks; a high pulsatility index or notching means high resistance and risk; not useful alone in low-risk women
Placental growth factor and sFlt-1	Low placental growth factor, or a high sFlt-1 to placental growth factor ratio, supports the diagnosis in women with suspected pre-eclampsia (20–35 weeks); a ratio of 38 or less makes pre-eclampsia unlikely within a week (cut-offs depend on the assay)
Basic tests in suspected disease	Urine protein (strip, protein-to-creatinine ratio), blood count with platelets, liver and kidney tests, uric acid
Practical point	Where advanced tests are not available, risk factors, BP, and urine at every visit remain the mainstay

STEP 3 · PREVENT — the measures that work

💊 PREVENTION

Measure	Details
Low-dose aspirin	75–150 mg once daily at night (FIGO suggests 150 mg; ACOG suggests 81 mg) from 12 weeks, ideally before 16 weeks, until 36 weeks or birth; lowers preterm pre-eclampsia by roughly 60% in high-risk women when started early (from trials; effect varies)
Calcium	WHO: 1.5–2 g elemental calcium a day from 20 weeks in populations with low intake; India recommends about 1 g a day; give with iron at different times
Control chronic disease	Treat chronic hypertension (labetalol, nifedipine, or methyldopa; stop ACE inhibitors and angiotensin blockers); optimise diabetes and kidney disease
Lifestyle	Healthy weight before pregnancy, regular moderate physical activity, and balanced diet
Antiphospholipid syndrome	Aspirin plus low molecular weight heparin as advised by a specialist
What does not prevent it	Vitamins C and E, fish oil, garlic, bed rest, and salt restriction (not proven); low molecular weight heparin alone is not recommended for prevention
Spacing and planning	Interpregnancy intervals of 2 years or more and pre-pregnancy counselling

Start early: aspirin started after 16 weeks is less effective, but it may still be given if the woman is at high risk

STEP 4 · SURVEILLANCE — for women at risk

📋 MONITORING

Topic	Details
Every antenatal visit	BP with the correct cuff, urine protein, weight, symptoms, and fundal height
More visits for high-risk women	Every 2–4 weeks from 28 weeks; home BP monitoring where practical
Growth scans	From 28–32 weeks in high-risk women, with umbilical artery Doppler if growth is poor
Diagnosis	BP of 140/90 or more on two occasions 4 hours apart (or 160/110 once) with protein, or with organ dysfunction
Timing of birth	Pre-eclampsia without severe features: about 37 weeks; with severe features: from 34 weeks, earlier if unstable; senior decision
After birth	BP at days 3–6 (eclampsia can occur up to 6 weeks), continue treatment as needed; annual BP, glucose, and lipids because lifetime heart disease risk is higher
Next pregnancy	Counsel early, start aspirin at 12 weeks, and plan care

STEP 5 · COUNSEL — teach her what to watch for

💬 WARNING SIGNS TO TEACH

Topic	Advice
Come at once for	Severe headache, blurred vision or flashing lights, pain below the ribs, vomiting, sudden swelling of the face or hands, breathlessness, fits, or reduced movements
Take aspirin and calcium daily	Do not stop without advice; tell the doctor about bleeding or stomach pain
Plan delivery at a hospital	With a blood bank and newborn care
Family	Explain the signs and who to call; plan transport

⚠️ COMMON PITFALLS

Starting aspirin too late or not at all in a high-risk woman

Using the wrong cuff size or measuring BP after a long wait and missing hypertension

Waiting for protein to diagnose pre-eclampsia when other signs are present

Using placental growth factor tests to screen well women

Stopping BP checks after the first trimester or after birth

Giving calcium and iron together so absorption is poor

Forgetting long-term follow-up after pre-eclampsia

Memory Aid

SCREEN

Six steps for pre-eclampsia prediction and prevention.

S

Stratify — one high-risk or two moderate-risk factors

C

Calcium — 1–2 g a day where dietary intake is low

R

Rx aspirin — 75–150 mg nightly from 12 weeks, before 16 if possible

E

Every visit — BP, urine, symptoms, growth scans from 28 weeks

E

Educate — headache, vision, upper pain, swelling, fits, movements

N

Notify and refer — BP 160/110 or more, or severe features

Remember: identify the risk, start aspirin early, check BP at every visit, and act fast on severe signs.

Swaraj Hospital & Research Institute · Department of Obstetrics & Gynaecology, Bolangir, Odisha

Clinician-facing summary drawn from memory of National Institute for Health and Care Excellence (NICE), American College of Obstetricians and Gynecologists (ACOG), International Federation of Gynecology and Obstetrics (FIGO), Fetal Medicine Foundation, and World Health Organization (WHO) guidance; no source was read for this sheet. No Government of India document was read: the Indian calcium recommendation is from memory, so check the Ministry of Health and Family Welfare guidelines. Aspirin dose and timing, calcium dose, screening performance, and timing of birth vary between guidelines and must be set by the senior obstetrician; thresholds, intervals and regimens vary between guidelines — follow local protocol and involve a senior obstetrician in any high-risk case.