ABSTRACT
OBJECTIVE: The purpose of this study was to establish the reference range for the sonographically estimated fetal weights (EFW) in twin gestations at 26 to 38 weeks' gestation. METHODS: This is a retrospective study of EFW that were obtained from electronic medical records of live births of all twins delivered between June 2003 through August 2007 at Seoul National University Bundang hospital. EFW was calculated using the mathematical model of Hadlock and only one measurement from each twin was used. Linear regression and Kolmogorov-Smirnov test were used for statistical analysis. RESULTS: Three hundred and forty-three twin pregnancies (686 fetuses) were included in this study. Reference range for EFW in twin gestations was presented as mean, standard deviation and percentiles. Scatterplots of EFW against gestational age (GA) were created with regression line of best fit and a linear growth function was observed between GA and EFW between 26 and 38 weeks' gestation (EFW=161.807 X GA - 3349.735 (r2=0.861, p<0.001). CONCLUSIONS: We established the reference range for EFW in twin gestations at 26 to 38 weeks' gestation. These results can be used as reference guidelines in the assessment of fetal growth restriction in Korean twin pregnancies.