CLINICAL TOOL
First-Trimester Clinical Workbench
Comprehensive first-trimester risk assessment workbench. Integrates ultrasound markers, maternal history, and biochemistry using a competing risks approach.
Clinical Purpose
To provide advanced patient-specific risk estimation for chromosomal anomalies (Trisomy 21, 18, 13), preeclampsia, and fetal growth restriction in the first trimester (11-13+6 weeks).
Inputs
- Maternal characteristics and medical history
- Ultrasound markers (NT, CRL, Nasal Bone, Tricuspid Regurgitation, Ductus Venosus)
- Biomarkers (PAPP-A, free β-hCG, PlGF)
- Biophysical parameters (MAP, Uterine Artery PI)
Formula & Guideline Source
Fetal Medicine Foundation (FMF) algorithms and multi-center validation studies.
Limitations
Risk calculation is a screening process, not a definitive diagnosis. High-risk results should be followed by diagnostic testing (e.g., CVS or Amniocentesis) and expert clinical counseling. This tool is for educational and supportive purposes and does not replace clinical judgment.
FAQ
When is the optimal time for the first-trimester scan?
The optimal time is between 11 weeks and 13 weeks + 6 days of gestation, corresponding to a crown-rump length (CRL) of 45 to 84 mm.
How does the competing risks model differ from traditional screening?
A competing risks model considers that the occurrence of one event (e.g., delivery at a given gestation) precludes the occurrence of another (e.g., developing preeclampsia at a later gestation). This provides a more accurate, personalized risk trajectory.
References
- Nicolaides KH. Turning the pyramid of prenatal care. Fetal Diagn Ther. 2011.
- Wright D, et al. A competing risks model in early screening for preeclampsia. Fetal Diagn Ther. 2012.
- O'Gorman N, et al. Competing risks model in screening for preeclampsia by maternal factors and biomarkers at 11-13 weeks' gestation. Am J Obstet Gynecol. 2016.