AbstractObjectiveTo investigate the fetal brain activity in pre‐eclamptic and normal pregnancies. Biomagnetic measurements were performed by means of a superconducting quantum interference device (SQUID) in an electrically shielded room of low magnetic noise.MethodsThe study population included 28 pre‐eclamptic (34–37 weeks' gestation) and 19 normal pregnancies (34–37 weeks' gestation). The pre‐eclamptic group consisted of 11 cases with birth weight below the 10th percentile (1969 ± 129 g) and 17 cases above the 10th percentile (2496 ± 257 g). Biomagnetic signals (waveforms) recorded from fetal brains were expressed in terms of magnetic power spectral amplitudes.ResultsThe total corresponding spectral amplitudes in the frequency range 2–7 Hz were high (719 ± 69 Ft/√Hz in neonates <10th percentile and 537 ± 105 Ft/√Hz in neonates >10th percentile) in most (82%) pre‐eclamptic pregnancies and low (382 ± 35 Ft/√Hz) in most normal pregnancies (95%). The difference between normal and all pre‐eclamptic pregnancies was highly significant (Student's t‐test: p < 0.0001). Comparing the two groups of pre‐eclampsia we found also a highly significant difference (Student's t‐test: p < 0.0001).ConclusionBiomagnetic measurements of fetal brain activity could be useful in the assessment of fetal central nervous system development. Copyright © 2002 John Wiley & Sons, Ltd.