Mechanical vibrations induced by the heart of the foetus, together with other vibrations coming from the body of the pregnant mother, are sensed by the at least one electro-mechanical transformer placed on the body surface of the pregnant mother, the vibrations are transformed into electrical signals and processed. The electrical signals are pre-amplified, frequencies including the heart sound of the pregnant mother are removed from amplified electrical signals of the perceived vibrations by active bandpass filtering, the signal level reduction due to bandpass filtering is compensated for by amplification, and the filtered signal is transferred to a device for processing and evaluation. A device suitable for implementing the method, and a computer-readable medium are proposed, the latter comprising instructions to be run on the device, e.g. the smartphone, for processing the measured signals, displaying them visually, showing trends and making proposals to the user based on the processed signals.
