Direct foetal electrocardiography doses help the experienced examiner to detect cardiac arrhythmia. It can be an early signal of imminent danger. However, errors may occur to the interpreter of foetal electrocardiograms. They may be caused by materno-foetal ECG conduction in a case of intra-uterine foetal death, appearance of maternal pulses in the foetal curve, errors in pole connection of the scalp electrode, and superposition of alternating current on the ECG curve. Knowledge of those potential sources of error is essential, if erroneous decisions are to be avoided.