Accuracy of different equations for estimating fetal weight.

Area of Science:

• Obstetrics and Gynecology
• Medical Imaging
• Perinatology

Background:

• Accurate fetal weight (FW) estimation is crucial for managing singleton pregnancies.
• Ultrasound-based equations are commonly used, but their accuracy varies.
• Evaluating existing FW estimation formulas is essential for clinical practice.

Purpose of the Study:

• To assess the predictive accuracy of ten different ultrasound-based equations for estimating fetal weight (FW).
• To compare the performance of these equations against actual birth weight (BW) measurements.

Main Methods:

• A cross-sectional study involving 250 healthy women with singleton pregnancies (34-41 weeks gestation).
• Fetal weight (FW) was estimated using ten distinct equations.
• Estimated FW was compared to birth weight (BW) measured within 72 hours post-estimation.
• Analysis included error rates, intraclass correlation, and agreement between estimated FW and BW.

Main Results:

• The majority of the ten evaluated equations demonstrated significant inaccuracy in predicting birth weight (BW).
• Only two equations achieved acceptable accuracy, with less than 10% of measurements within a 10% error margin.
• Four formulas tended to overestimate FW, while six formulas showed a tendency to underestimate FW.

Conclusions:

• There is a need for developing more accurate fetal weight (FW) estimation equations applicable across diverse populations.
• Clinicians should verify the accuracy of available fetal growth equations against local data or established growth curves when local data is unavailable.