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.
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?
The high-risk cut-off and aspirin protocol depend on the validated screening model and the applicable local guideline. The result should be reviewed by the responsible clinician, who will confirm whether aspirin is appropriate, its dose, timing, contraindications, and stop date.
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.