PRECISION OF SONOGRAPHIC WEIGHT ESTIMATIO N - COMPARISON OF VERTEX VERSUS BREECH PRESENTATIONS

Aim: To determine the quality of prenatal sonographic weight estimatio n, comparing breech and vertex presentations. Method: In 147 breech pr esentations (BP) and 149 vertex presentations (VP), the biparietal hea d diameter (BPD), the fronto-occipital head diameter (FOD) and the tra nsverse abdominal diameter (ATD) were measured. From these data, the w eight was estimated, using Shepard's formula before 28 weeks and Hansm ann's thereafter, and compared to the delivery weight. Both formula we re modified to incorporate the virtual BPD (vBPD), derived from the BP D, FOD and the calculated head circumference. In the BP group, the rol e of examiner skills was evaluated, comparing the accuracy of experien ced (DEGUM II qualifications) and average individuals. Results: The ac curacy for BP was nearly identical to that for VP (= 0.915 vs. = 0.929 ). The examiners' qualifications had a detectable but not significant influence on the results (= 0.942 vs. = 0.892). Conclusion: Ultrasound measurements yield comparable results in both BP and VP, if the vBPD is used. In our opinion, ultrasonic weight estimation is a useful adju nct when determining the manner of delivery in BP.