Biophysical profile in the fetus from a phonographic sensor.

We have recently developed a phonographic transducer which is compliance-matched to the maternal abdomen. Using it, it is possible to monitor for long time periods, non-invasively and without discomfort, the sound and infra-sound produced by the fetus. Fetal heart sounds, fetal breathing, and fetal body movements can be recorded overnight in hospital or at home, and thereby provide a biophysical profile of fetal activity. Overnight recordings of fetal sounds and infra-sound together with maternal ECG and maternal breathing movements are currently being used to study mothers with normal and abnormal pregnancies.