CLINICAL TOOL

First Trimester Preeclampsia Screening

Calculate the risk of developing early-onset preeclampsia using the Fetal Medicine Foundation (FMF) algorithm, combining maternal factors, MAP, UTPI, and PLGF.

About this page

This is a clinician-reviewed evidence brief, not an interactive calculator. It summarises the guideline logic our subspecialists apply when managing these cases every day. For a case-specific assessment, request a consultation or refer your patient.

Request Consultation Refer a Patient Preeclampsia Screening — Patient Guide

Clinical Purpose

To identify women at high risk for preterm preeclampsia (before 37 weeks) at 11-13+6 weeks of gestation, allowing for the prophylactic administration of low-dose aspirin to significantly reduce the risk.

Inputs

Maternal Demographic Factors (Age, Weight, Height, Race)
Medical History (Chronic Hypertension, SLE, APS, Diabetes)
Obstetric History (Prior Preeclampsia, Parity)
Mean Arterial Pressure (MAP)
Uterine Artery Pulsatility Index (UTPI)
Placental Growth Factor (PLGF) and PAPP-A MoM

Formula & Guideline Source

Fetal Medicine Foundation (FMF) Competing Risks Model, ASPRE Trial.

Limitations

Screening is most effective when combining all biomarkers, but can be adapted if PLGF or UTPI are unavailable (with reduced detection rates). The algorithm is specific to the FMF model and requires certified sonographers for UTPI measurement.

FAQ

What is considered high risk?

A risk cut-off of 1 in 100 or 1 in 150 (depending on national guidelines) is generally used to define a high-risk group that would benefit from prophylactic aspirin (150 mg nightly from 12 to 36 weeks).

Can I screen if I don't have PLGF results?

Yes, the FMF algorithm can calculate a risk based solely on maternal factors, MAP, and UTPI, though the detection rate will drop from approximately 90% (with PLGF) to around 75-80%.

References

Rolnik DL, et al. Aspirin versus Placebo in Pregnancies at High Risk for Preterm Preeclampsia (ASPRE trial). N Engl J Med. 2017.
Wright D, et al. Predictive performance of the competing risk model in screening for preeclampsia. Am J Obstet Gynecol. 2019.