P14.67: Ultrasound estimation of fetal weight in prolonged pregnancy

Introduction: When performing fetal biometry measurements, the examiner occasionally has the impression that the sonographic estimation is less accurate due to technical limitations. Our objective was to evaluate the possible association between the examiners assessment of the measurement accuracy and the actual error between fetal weight estimation and actual birth weight. Methods: 186 women, within 10 days of delivery, were examined prospectively using fetal biometric measurements. Fetal weight estimates were calculated using Hadlock’s formula employing FL, AC and BPD. The sonographers were asked to give a subjective score to each measurement; one point if the quality of the measurement was technically good, two points if the measurement was of medium quality and three points if the measurement was of poor quality. The difference between the corrected sonographic fetal weight estimation and the actual birth weight was analyzed with respect to the scoring given by the examiner. Results: As shown in tables 1–3 for none of the three measured parameters did the perceived measurement accuracy predict the actual error in predicting birth weight.