Non-nutritive sucking recorded in utero via fetal magnetography

Several studies in term and pre-term infants have investigated the rhythmic pattern of non-nutritive sucking (NNS) indicating correlations between the quantitative measures derived from sucking pressure variation and/or electromyographic (EMG) recordings and a range of factors that include age, perinatal stress and sequelae. In the human fetus, NNS has been reported from 13 weeks of gestation and has been studied using real-time Doppler ultrasonography exclusively. The present study indicates that NNS in fetus can be reliably recorded and quantified using non-invasive biomagnetic measurements that have been recently introduced as an investigational tool for the assessment of fetal neurophysiologic development. We show that source separation techniques, such as independent component analysis, applied to the high-resolution multichannel recordings allow the segregation of an explicit waveform that represents the biomagnetic equivalent of the ororhythmic sucking pressure variation or EMG signal recorded in infants. This enables the morphological study of NNS patterning over different temporal scales, from the global quantitative measures to the within burst fine structure characterization, in correlation with the fetal cardiac rhythm.