OP29.06: Mid-second trimester abdominal circumference ratio in a twin gestation predicts poor perinatal outcome

LCN between twins, first trimester discrepancy identified 3 cases and only one of them was discordant at delivery. So, LCN discrepancy was not a predictor of birthweight discordance by any of these methods (p = 0.72 and p = 0.63 for chi-squared tests respectively). ROC curve using FHTV discrepancy (in %) suggested a significant prediction on birthweight discrepancy. The area under curve was 0.76 and the analysis suggested that the best cut-off was between 15 and 20% of discrepancy reaching sensitivity and specificity around 80%. With a cut-off of 15% 13 cases of first trimester discrepancy were identified. From them, 8 were discordant at delivery (61.5%). So, the identification of 88.9% of cases of birthweight discrepancy (8/9). Conclusions: Measurements of first trimester FHTV can be useful for predicting birthweight discordance.