Early Pregnancy · PE Screening
FMF First-Trimester PE Screen
Enhanced first-trimester screening for pre-eclampsia at 11-13+6 weeks. Combines history + MAP + uterine artery Doppler + PlGF. ~75% detection of preterm PE (vs ~40% history alone). Triggers aspirin prophylaxis. ASPRE trial NEJM 2017.
Last reviewed 2 June 2026
FMF First-Trimester PE Screen
Preeclampsia Bayesian risk — 11-13+6 weeks
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Enter prior risk; markers in MoM if known.
Educational tool only — simplified Bayesian model. Real FMF calculator uses competing-risks regression. Use the official FMF tool at fetalmedicine.org for clinical decisions. Triple test (maternal + MAP + UtA-PI + PlGF) achieves ~90 % detection of preterm PE at 10 % FPR.
What does this mean?
The FMF first-trimester PE screen combines four numbers at 11–13+6 weeks: maternal characteristics (age, BMI, ethnicity, parity, prior PE, chronic HTN, T1DM), mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI) on ultrasound, and serum PlGF. The full triple-test approach detects ~90 % of preterm PE at 10 % FPR(Nicolaides & Poon, multiple cohorts). Women screened high-risk get aspirin 150 mg nightly from 11–14 wk — the ASPRE trial (NEJM 2017) showed this cuts preterm PE by 62 %. Many countries (UK NHS England 2025, FIGO 2019, NICE) are moving toward FMF-style first-trimester screening as the standard of care. If your unit doesn’t offer triple-test, the simpler clinical risk-factor screen (USPSTF / ACOG) still identifies most candidates for aspirin prophylaxis.
What is the FMF PE screen?
Enhanced screening at 11-13+6 weeks combining:
- Maternal factors (age, BMI, ethnicity, parity, history).
- Mean Arterial Pressure (MAP).
- Uterine artery Doppler pulsatility index.
- PlGF (placental growth factor) blood test.
- Sometimes PAPP-A.
~75% detection of preterm PE at 10% screen-positive rate.
Why add to NHS care?
NHS booking uses history alone. FMF catches ~50% more women who’d benefit from aspirin. ASPRE trial: aspirin reduced preterm PE by 62% in high-risk women.
Where to get it
- Private clinics (Harmony, FMC, private maternity hospitals).
- NHS at Belfast, parts of London, some teaching hospitals.
- Some private GPs.
- Cost: £200-400 private; free where NHS offers.
What if high-risk?
- Aspirin 150 mg nightly from <16 weeks.
- BP at every visit; urine dipsticks.
- Bloods 28+ weeks.
- Growth scans 28, 32, 36 weeks.
- Specialist consultant care.
What if low-risk?
Standard antenatal care. Reassuring — but doesn’t guarantee no PE. Still call midwife if warning symptoms develop.
Different scenarios
Scenario 1: 32 years old, BMI 28, family history of PE, first baby
FMF screen worth doing. If high-risk, aspirin + specialist care.
Scenario 2: Previous PE at 36 weeks, planning second baby
FMF screen + aspirin from positive test regardless of screen.
Scenario 3: 11 weeks pregnant, BMI 35, age 38, chronic hypertension
FMF screen + aspirin near-certain. Specialist clinic.
Scenario 4: Missed 14-week window
Full algorithm not valid. Alternative: 2nd-trimester uterine artery Doppler at 20-24 wk.
Scenario 5: Low-risk screen, normal pregnancy
Reassuring. Standard care continues.
Care guidance
- Book 11-13+6 weeks.
- Bloods + ultrasound in same appointment.
- Results inform aspirin decision.
- NHS care continues regardless.
- Doesn’t replace anomaly scan or routine visits.
Sources
- Rolnik DL, et al. ASPRE: Aspirin versus Placebo in Pregnancies at High Risk for Preterm Preeclampsia. NEJM 2017.
- Fetal Medicine Foundation. First-trimester combined screening for preeclampsia.
- NICE NG133. Hypertension in pregnancy.
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Frequently asked questions
What is the FMF first-trimester PE screen?
Enhanced screening test for pre-eclampsia (PE) done at 11-13+6 weeks. Combines: (1) MATERNAL FACTORS (age, BMI, ethnicity, parity, history); (2) MEAN ARTERIAL PRESSURE (MAP) — averaged BP; (3) UTERINE ARTERY DOPPLER pulsatility index (PI); (4) PIGF (placental growth factor) blood test; (5) sometimes PAPP-A. Algorithm by Fetal Medicine Foundation (FMF). DETECTION RATE: ~75% of preterm PE (delivery <37 weeks) with 10% screen-positive rate. SUPERIOR to history-alone screening.
Why have FMF screen on top of NHS care?
NHS UK risk assessment at booking uses HISTORY alone (previous PE, BMI, age, etc.). FMF SCREEN: catches ~50% MORE women who'd benefit from aspirin. ASPRE trial (NEJM 2017): aspirin from <16 weeks reduced preterm PE by 62% in high-risk women selected by FMF screen. WORTH IT FOR: women interested in proactive screening; those with family history; private maternity package. INCLUDED in some NHS trusts; private £200-400.
Where do I get FMF screening?
(1) PRIVATE early pregnancy / NIPT clinics — many offer (Harmony, Foetal Medicine Centre, FMC, private maternity hospitals); (2) NHS — Belfast, parts of London, some teaching hospitals offer routinely; varies by trust; (3) SOME private GPs through scan + bloods; (4) SELF-REFERRAL possible. COST: £200-400 private; free where NHS offers. NOT all private scan clinics include the full FMF algorithm — confirm before booking.
What's PlGF?
PLACENTAL GROWTH FACTOR — protein produced by placenta. LOW PlGF in early pregnancy associated with PLACENTAL DYSFUNCTION → pre-eclampsia + fetal growth restriction risk. PlGF + sFlt-1 ratio also used LATER in pregnancy (20+ weeks) for diagnosing/predicting PE in women with symptoms. EARLY (11-13 wk) PlGF: predicts later PE risk. LATER: differentiates true PE from other hypertension.
What does uterine artery Doppler show?
BLOOD FLOW through uterine arteries (which supply placenta). EARLY pregnancy: should be HIGH FLOW (low resistance) as placenta develops. HIGH RESISTANCE (high pulsatility index) at 11-14 weeks suggests placenta not invading uterine wall properly — predicts PE, growth restriction. PROVIDES PHYSIOLOGICAL INSIGHT not available from history alone. PERFORMED with same scan probe as nuchal scan; takes a few extra minutes.
What if my FMF screen is high-risk?
ASPIRIN 150 mg nightly from <16 weeks. Start immediately. INTENSIVE monitoring: BP at every visit; urine dipsticks; bloods 28+ weeks; growth scans 28, 32, 36 weeks. SPECIALIST consultant care. PRECONCEPTION optimisation before next pregnancy if applicable. AT HIGH-RISK CLINIC: continuous monitoring; quick access if symptoms. PROACTIVE care often prevents progression to severe PE.
What if it's low-risk?
REASSURING — but doesn’t guarantee no PE. STANDARD ANTENATAL CARE continues. NORMAL monitoring at appointments. STILL CALL midwife if PE warning symptoms develop (severe headache, visual changes, RUQ pain, swelling). LOW RISK ≠ zero risk; PE can develop in low-risk pregnancies (~5% miss rate with FMF screen).
Is the screen accurate?
FMF algorithm: ~75% detection of preterm PE (delivery <37 wk) at 10% screen-positive rate. ~40% detection for ALL PE (lower for late-onset, which is less severe). NPV (negative predictive value): ~95% don't develop PE if low-risk. FALSE POSITIVES happen — ~10% screen positive but never develop PE. EARLY-ONSET PE is the most dangerous form; FMF best at detecting this.
Do I need bloods AND ultrasound?
YES — full algorithm needs both. BLOODS for PlGF + PAPP-A (combined or separate); ULTRASOUND for MAP measurement, uterine artery Doppler, dating, nuchal translucency. CAN BE DONE in single appointment. SOME providers offer 'bloods only' partial algorithm — less accurate. FULL FMF protocol gives best detection.
What's the difference from NIPT?
DIFFERENT TESTS. NIPT (cffDNA): screens for CHROMOSOMAL conditions (Down, Edwards, Patau). FMF PE screen: predicts PRE-ECLAMPSIA risk. Both done around 11-13 weeks. SOME providers bundle both together. COMPLEMENTARY information. PARENTAL choice — many high-risk women have both.
How does this fit with NHS care?
ENHANCEMENT to standard NHS antenatal care. Results shared with GP/midwife. NHS booking risk assessment continues separately. ASPIRIN prescription can be obtained via NHS GP if FMF screen high-risk (informed clinical judgement). Some trusts INTEGRATE FMF results into care plan. NEVER REPLACES routine NHS antenatal visits, anomaly scan, etc.
Will FMF screen affect my insurance?
GENERALLY NO. FMF results = risk estimate, not a diagnosis. PRIVATE health insurance pregnancy cover: usually unaffected (pregnancy already excluded or covered). LIFE / health insurance: positive screen could theoretically be disclosed if asked. CONSULT insurance adviser. MOST PEOPLE: no impact.
Can I have the screen if I missed the 11-14 week window?
FULL ALGORITHM only valid 11+0 to 13+6 weeks. AFTER 14 weeks: nuchal translucency unreliable; uterine artery Doppler less useful. ALTERNATIVES: SECOND-trimester screen (uterine artery Doppler at 20-24 wk only, less accurate); HISTORY-based risk assessment alone; PlGF/sFlt-1 ratio after 20 weeks if symptoms develop. WORTH BOOKING EARLY (e.g. at 8-10 weeks for 12-week scan).
Will I need a follow-up?
STANDARD: low-risk just continue normal antenatal care. HIGH-RISK: aspirin from <16 weeks; intensive monitoring; specialist clinic; growth scans third trimester. SOME PROTOCOLS include INTERMEDIATE risk — monitoring increased but no aspirin unless other factors. RE-ASSESSMENT at 20-week anomaly scan can update risk picture.
How does this relate to other calculators on BumpBites?
Companion: /calculators/preeclampsia-risk for history-based assessment; /calculators/preeclampsia-diagnosis if PE develops; /calculators/aspirin-pe-prevention for prophylaxis; /calculators/first-trimester-screen for nuchal/chromosomal; /calculators/nipt-cfdna; /calculators/hellp-classifier.