Comparing fetal ultrasound biometric measurements to neonatal anthropometry at the extremes of birthweight.

Using a standardized ultrasound protocol, SGA neonates had ultrasound measurements closer to actual birth measurements compared to AGA or LGA neonates. LGA neonates had the largest differences between fetal and neonatal size, with measurements 14 days from delivery showing 3-4-fold greater differences from birthweight. Differences in EFW and birthweight may not be explained by a single fetal measurement; whether estimation may be improved by incorporation of other knowable factors should be evaluated in future research.