Pre-eclampsia risk calculator (first trimester)

First-trimester screening model combining maternal history, blood pressure, uterine artery Doppler and PlGF.

Appears only on the printed report. It is not sent or stored.

Maternal history

Maternal measurements

Doppler and biochemistry

Use the values from your first-trimester scan. The uterine artery pulsatility index (PI) is measured between 11 weeks and 13 weeks 6 days.

Optional. If you do not have the value, leave it blank: the calculation assumes 1.0 MoM.

How the risk is calculated

The model combines the a-priori probability (age, ethnicity, parity, chronic hypertension, kidney disease and previous pre-eclampsia) with three first-trimester measurements: mean arterial pressure in multiples of the median (MoM), mean uterine artery pulsatility index in MoM and PlGF in MoM. The output is an absolute risk of early pre-eclampsia, meaning before 34 weeks.

First-trimester screening identifies high-risk pregnancies early in prenatal care, when low-dose aspirin and closer follow-up have the greatest impact. Derm Imagem performs first-trimester ultrasound with crown-rump length, nuchal translucency and uterine artery Doppler in Ipatinga, Brazil.

Model and references

First-trimester screening model for early pre-eclampsia published by:

  1. Crovetto F, Figueras F, Triunfo S, et al. First trimester screening for early and late preeclampsia based on maternal characteristics, biophysical parameters, and angiogenic factors. Prenat Diagn. 2015;35(2):183-191. doi:10.1002/pd.4519

Reference calculator: calc.fetalmedicinebarcelona.org/preeclampsia

Supporting risk-factor data: Bartsch E, Medcalf KE, Park AL, Ray JG. Clinical risk factors for pre-eclampsia determined in early pregnancy: systematic review and meta-analysis of large cohort studies. BMJ. 2016;353:i1753. doi:10.1136/bmj.i1753

Independent reproduction of the published models, for educational purposes.

Frequently asked questions

It is a pregnancy complication characterised by high blood pressure and protein in the urine, or other signs of organ damage, after 20 weeks. The early form, before 34 weeks, carries the highest risk for mother and baby.

Screening is performed between 11 weeks and 13 weeks 6 days, when crown-rump length is between 45 and 84 mm and nuchal translucency and uterine artery Doppler can be measured.

No. PlGF improves the accuracy of the model, but the calculation works without it: in that case the tool assumes 1.0 MoM, the population average.

Take the result to your obstetrician. High risk does not mean pre-eclampsia will occur, but it does indicate the need for closer follow-up and, usually, low-dose aspirin from the first trimester.

Important notice

This calculator is an educational tool and does not replace a medical consultation. Results are estimates based on published models and may not apply to your case. Never make decisions about your health or your pregnancy without advice from your doctor.

Reviewed by: Dr. Peterson Fernandes — CRM-MG 42452 · RQE 37814

Last reviewed: 11/3/2026

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