Fetal magnetoencephalographic mapping in normal and pre-eclamptic pregnancies.

This study investigates the fetal brain activity in normal and pre-eclamptic pregnancies. Measurements were performed by means of a superconducting quantum interference device (SQUID) in an electrically shielded room of low magnetic noise. The study was prospective. Ten pregnant women with pre-eclampsia and 11 healthy gravidae were included. All were preterm at 28 to 37 weeks' gestation. Biomagnetic signals (waveforms), recorded from the fetal brains in the frequencies 2-7 Hz, were expressed in terms of magnetic power spectral amplitudes: these were low in almost all normal pregnancies, and high in most pregnancies complicated with pre-eclampsia. The pictorial representation of the results in the form of iso-spectral amplitude (ISO-SA) mapping showed two different patterns: (a) iso-contour lines 'organised' in dense concentration zones (pre-eclamptic pattern), (b) iso-contour lines at random distribution without dense concentration zones (normal pattern). Biomagnetic measurements of fetal brain activity is a promising screening procedure for assessing the cerebral function, especially at high risk pregnancies.