Accuracy of ultrasound in estimating fetal weight and growth discordancy in triplet pregnancies.

Abstract

Sonographic estimation of fetal weight is a fundamental part of the routine obstetrical practice and may affect management decisions particularly in multiple gestations. The data available on the accuracy of sonographic estimation of fetal weight in triplets are very limited. In the present study we investigated the accuracy of sonographic fetal weight estimation and discordancy in triplet gestations. We analyzed the sonographic data of 33 sets of triplets born at one medical center between January 2001 and March 2013. Estimated fetal weight was calculated from biometric measurements and compared with actual neonatal weights following delivery. The Pearson correlation coefficient, linear regression analyses, and Bland-Altman method were used for statistical comparisons. The differences between predicted and actual birth weights (ABW) were <10% in 69 newborns (70%), 10%-20% in 19 newborns (19%), and more than 20% in 11 newborns (11%). There was a good correlation between predicted and ABW (correlation coefficient=0.928, r2=0.86, P<0.0001). Weight assessment in triplets does not fall behind that of singletons or twins, and decisions based upon these examinations are reliable in the majority of cases.