A transducer for detecting foetal breathing movements using PVDF film

Foetal breathing movement (FBM) in utero has come to play an important role in foetal diagnosis. FBM may be monitored using real time ultrasound imaging of the foetus in utero. Foetal breathing activities can also be detected by monitoring maternal abdominal wall movement in the frequency range of 0.5-2.5 Hz. This paper presents a transducer which detects FBM non-invasively by monitoring maternal abdominal wall movements. Foetal heart sounds can also be monitored. The transducer presented uses piezo-electric film as the transducing medium. Results from preliminary clinical trials of prototype transducers on 10 patients are discussed.