Correctly identifying the macrosomic fetus: improving ultrasonography-based prediction

Area of Science:

• Medical imaging
• Obstetrics
• Fetal medicine

Background:

• Accurate estimation of fetal weight is crucial for managing macrosomic fetuses.
• Traditional methods using abdominal circumference, femur length, and head circumference have limitations in precision.

Purpose of the Study:

• To enhance the accuracy of estimating fetal weights in macrosomic fetuses.
• To compare a novel adjusted method with the established Hadlock et al. equation.

Main Methods:

• Utilized a dataset of 4831 ultrasonography cases without anomalies.
• Regressed standard fetal measurements against birth weight, incorporating adjustments for delivery date, maternal factors, and specific birth weight thresholds.
• Calculated within-subject standard deviation to assess measurement variability.

Main Results:

• The adjusted method achieved higher sensitivity (85.7% vs. 71.4%) at 95% specificity for identifying macrosomic fetuses compared to the Hadlock et al. equation.
• Identified specific indicators, such as abdominal circumference exceeding other measurements or high within-subject variance, associated with increased risk of macrosomia.

Conclusions:

• The developed approach offers improved accuracy in identifying macrosomic fetuses over the current "one function fits all" model.
• Maternal characteristics and specific measurement discrepancies are vital for refining fetal weight estimation.
• Further validation is recommended for clinical optimization.