Finding the most accurate method to measure head circumference for fetal weight estimation

Area of Science:

• Perinatal medicine
• Medical imaging
• Obstetrics

Background:

• Accurate fetal weight estimation (FWE) is crucial for neonatal outcomes and obstetric management.
• Head circumference (HC) is a key parameter in many FWE equations.
• Optimizing HC measurement is essential for reliable FWE.

Purpose of the Study:

• To identify the most accurate ultrasound method for measuring fetal head circumference (HC) for fetal weight estimation (FWE).
• To compare the accuracy of different HC measurement techniques and their impact on FWE.

Main Methods:

• Prospective study of 481 term pregnancies with singleton fetuses.
• Compared ultrasound HC measurements (ellipse-traced, ellipse-calculated, circle-calculated) against a postnatal reference.
• FWE performed using Hadlock formulas with HC or biparietal diameter (BPD); accuracy assessed by percentage error (PE), absolute percentage error (APE), and limits of agreement (LOA).

Main Results:

• The ellipse-traced method demonstrated superior accuracy for FWE compared to other ultrasound techniques.
• Ellipse-traced HC yielded the lowest median APE and narrowest LOA.
• Biparietal diameter (BPD) measurements showed accuracy comparable to the ellipse-traced HC method for FWE.

Conclusions:

• While differences between HC calculation methods are small, the ellipse-traced technique is recommended for clinical FWE.
• Biparietal diameter (BPD) offers a clinically useful alternative to HC for fetal weight estimation due to similar accuracy.
• Standardizing HC measurement and considering BPD can improve FWE accuracy and clinical decision-making.