Analysis of factors influencing the ultrasonic fetal weight estimation

Objective: The aim of our study was the evaluation of sonographic
fetal weight estimation taking into consideration 9 of the most
important factors of influence on the precision of the estimation.
Methods: We analyzed 820 singleton pregnancies from 22 to 42 weeks
of gestational age. We evaluated 9 different factors that
potentially influence the precision of sonographic weight
estimation ( time interval between estimation and delivery, experts
vs. less experienced investigator, fetal gender, gestational age,
fetal weight, maternal BMI, amniotic fluid index, presentation of
the fetus, location of the placenta). Finally, we compared the
results of the fetal weight estimation of the fetuses with poor
scanning conditions to those presenting good scanning conditions.
Results: Of the 9 evaluated factors that may influence accuracy of
fetal weight estimation, only a short interval between sonographic
weight estimation and delivery (0-7 vs. 8-14 days) had a
statistically significant impact. Conclusion: Of all known factors
of influence, only a time interval of more than 7 days between
estimation and delivery had a negative impact on the estimation.