Optimal standards for fetal biometry: to each measurement its fitting model

Area of Science:

• Prenatal diagnostics
• Fetal biometry
• Medical imaging analysis

Background:

• Accurate fetal growth assessment is crucial for monitoring pregnancy.
• Existing mathematical models for fetal measurements vary in complexity and applicability.
• Fetal head measurements have previously shown optimal fit with a two-phase model.

Purpose of the Study:

• To identify the optimal mathematical model for constructing fetal abdominal circumference (AC) and femur length (FL) growth charts.
• To compare the performance of four distinct mathematical models in fitting AC and FL data.
• To establish reliable centile charts for fetal AC and FL based on the best-fitting model.

Main Methods:

• Ultrasound measurements were collected from 1,336 normal fetuses.
• Four mathematical models were evaluated: linear-quadratic, linear-cubic, Rossavik, and a novel two-phase model.
• Model performance was assessed based on the goodness-of-fit for fetal AC and FL data.

Main Results:

• The linear-quadratic model demonstrated the best fit for both fetal AC and FL data.
• Optimal fitting was achieved without the need for gender-specific calculations.
• Centile charts for fetal AC and FL were successfully computed using the selected model.

Conclusions:

• Fetal growth of AC and FL exhibits a simpler pattern compared to fetal head growth.
• A single, universal mathematical model is not suitable for all fetal biometric measurements.
• The linear-quadratic model provides a robust framework for AC and FL charting in routine prenatal care.