Among the most interesting and most compelling areas of biomagnetism is fetal biomagnetism. Routine investigation of fetal electrophysiology has not been possible due to the poor quality of surface fetal electric recordings. It is believed that the transmission of electric signals is impeded by vernix, a waxy substance of low electrical conductivity that forms on the baby’s skin. But because fetal magnetic signals are less affected by vernix, they can be recorded with much higher quality, thus opening a whole new area of investigation.
The most promising clinical application of fetal biomagnetism is diagnosis of fetal heart rhythm disorders via fetal magnetocardiography (MCG). FMCG is also potentially useful for assessment of fetal well-being. A very interesting, but challenging, area of current research is fetal MEG. This is perhaps the only way in which brain activity can be directly recorded in utero.