EP14.08: Sonographic prediction of birthweight discordance in twin gestations

Birthweight discordance (BWD) in twin gestations is associated with an increased risk of adverse neonatal outcomes. The antenatal prediction of BWD may provide a window of opportunity to mitigate these outcomes. This study aimed to determine the performance of sonographic biometric parameters in predicting birthweight discordance in twin gestations. This was a cohort study of win gestations delivered in a single medical centre between 2013-2023. Twin gestations in whom sonographic estimation of fetal weight was performed within 14 days of delivery were included in the analysis. Logistic regression and Receiver-operating curves (ROC) were adopted to compare the performance of Estimated Fetal Weight (EFW), Abdominal circumference (AC), Femur length (FL) and Head circumference (HC) discordance (>10% intertwin difference for each parameter) for the prediction of Birthweight discordance (>18%). A total of 612 twins were included in the analysis. EFW and AC but not HC and FL discordancy was associated with a significantly increased risk of BW discordancy (odds ratio (OR) 2.6, 95% CI 1.5-4.4, p < 0.001), (OR 5.2, 95% CI 2.3-12.2, p < 0.0001) (OR 0.4 95% CI 0.02-2.2 p = 0.4), and (OR 3.5, 95% CI 0.8-14.5, p = 0.09) respectively. EFW discordance was associated with an Area Under the Curve of 0.82 (95% CI 0.74-0.89, p < 0.001) while AC, HC and FL discordance was associated with an AUC of 0.6(95% CI 0.48-0.67, p = 0.07), 0.6 (95% CI, 0.5-0.68, p = 0.04) and 0.6 (95% CI, 0.52-0.7, p = 0.01) for the prediction of birthweight discordance. EFW discordance > 10% serves as a significant and robust indicator for predicting birthweight discordancy, surpassing the predictive capabilities of abdominal circumference (AC), head circumference (HC), and femur length (FL) discordance.