An ultrasound fetal imaging system uses an acceleration sensor for generating an acceleration signal relating to movement of the ultrasound transducer. A user is guided in how or where to move the ultrasound transducer based on the results of image processing of the ultrasound images. The user can thus be guided to move the transducer in a certain direction so as to achieve a complete scan of a fetus in a shortest possible time. This limits exposure of the expectant mother to the ultrasound energy. The fetal image obtained may be used to determine a fetal weight, for example using regression analysis based on some of the parameters derived from the obtained image. Fig.2