[The value of prepartal ultrasound estimation of birth weight in breech presentation].

Biometric data, i.e. the biparietal (BPD) and fronto-occipital diameter (FOD) of the skull as well as the transverse (TTD) and the longitudinal trunk diameter (LTD) were obtained in 127 cases of breech and 95 cases of vertex presentations within one week before birth. These data were compared with the birth weight measured postpartally. From these data, an optimized equation was derived for both breech and vertex presentations and compared to the equation known from the literature. The optimized equation for breech presentations requires only the biometric data of the trunk (TTD and LTD). In spite of this optimization, the quality of the foetal weight estimation of breech presentations seems to be more inaccurate in comparison to the estimation of vertex presentations. Concerning the obstetrical management the foetal weight estimation by ultrasound has to be evaluated more critically for breech presentations than for vertex presentations.