Sonographic prediction of small and large for gestational age in breech-presenting fetuses

Introduction: To evaluate various sonographic estimated fetal weight (sEFW) formulas' accuracy for small-and large-for-gestational age (SGA/LGA) prediction in breech-presenting fetuses. Materials and methods: A retrospective analysis of all ultrasound-based fetal biometrical measurements performed within 3 days of delivery in term pregnancies, in one medical center (2007-2014). Overall, 274 breech- presenting fetuses (study group) were compared to 274 vertex-presenting fetuses (control group) matched by gender, gestational age and birth weight. sEFW was calculated by six previously published formulas. Accuracy was compared utilizing systematic error and random error for every formula. Prediction precision of SGA and LGA was evaluated by calculating each formula's sensitivity, specificity, +/- predictive value, and the area under the receiver-operating characteristic (ROC) curve (AUC). Results: Systematic error and random error varied greatly between formulas, ranging from -7.4% to 3.1%, 7.3% to 8.3% for the vertex-presenting fetuses and -8.9% to 1.9%, 7.9% to 8.6% for the breech-presenting fetuses, respectively. There was no statistical difference in small-or large-forgestational age prediction parameters between the groups. The highest sensitivity and specificity for prediction was achieved by same formula regardless of presentation. Conclusion: In our cohort, overall accuracy was slightly superior among vertex-presenting fetuses without difference in prediction accuracy for small-and large-for-gestational age neonates.