EFW
Pronunciation: ee-ef-double-you
Also written as: EFW — Estimated Fetal Weight
Estimated fetal weight, calculated measurement derived from ultrasound biometry to assess fetal size and growth.
Full Definition
Estimated fetal weight (EFW) is a calculated parameter derived from ultrasound biometric measurements, typically including biparietal diameter, head circumference, abdominal circumference, and femur length. Various mathematical formulas (such as Hadlock, Shepard, or Campbell equations) are used to estimate weight based on these measurements. EFW is essential for assessing fetal growth patterns, diagnosing growth disorders, and planning delivery management. The accuracy of EFW decreases with advancing gestational age and extremes of fetal weight, with typical margins of error of ±10-20%. EFW is expressed in grams and often reported with corresponding percentiles for gestational age to identify small-for-gestational-age or large-for-gestational-age fetuses.
Usage
Usage note: Always specify as estimated; accuracy limitations should be acknowledged.
In Context
- "EFW was calculated at 2,850 grams, placing the fetus in the 75th percentile for 36 weeks." — Third trimester ultrasound
- "Serial EFW measurements showed crossing of growth percentiles, concerning for IUGR." — Growth monitoring report