The systematic error in the estimation of fetal weight and the underestimation of fetal growth restriction

Area of Science:

• Obstetrics and Gynecology
• Fetal Medicine
• Diagnostic Imaging

Background:

• Fetal growth restriction (FGR) is linked to poor perinatal outcomes and long-term health issues.
• Antenatal diagnosis of FGR is challenging, with most cases undiagnosed.
• Current clinical practice often overlooks systematic errors in ultrasound-based estimated fetal weight (EFW).

Purpose of the Study:

• To highlight the impact of systematic error in ultrasound EFW on FGR underdiagnosis.
• To propose incorporating ultrasound EFW systematic error into FGR screening and surveillance strategies.
• To analyze the effect of EFW error on identifying fetuses at risk for FGR.

Main Methods:

• Development of an analytic model using published data from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Fetal Growth Studies.
• Quantification of the systematic error in ultrasound EFW.
• Evaluation of the impact of this error on FGR underdiagnosis across different risk percentiles (10th, 5th, 3rd).

Main Results:

• Systematic error in ultrasound EFW significantly contributes to the underestimation of fetuses with FGR.
• The magnitude of underdiagnosis is influenced by the chosen percentile for risk assessment.
• Analysis demonstrates a consistent underestimation bias across various risk thresholds.

Conclusions:

• The systematic error in ultrasound EFW is a critical, overlooked factor in FGR underdiagnosis.
• Current paradigms for identifying and managing fetuses at risk for FGR require modification to account for EFW systematic error.
• Integrating this error into clinical recommendations can improve antenatal detection rates and subsequent perinatal outcomes.