Electrodes and electrode positioning arrangement for detecting fetal electrocardiogram

A patch (140) of multiple electrodes for use with a fetal heart rate monitor, the patch multiple electrode comprising: a substructure (40) attachable to the flexible skin of a subject in pregnancy; at least three electrodes (142, 144, 146) positioned on the detection flexible substructure to approximate an arc; a common electrode (149) positioned in the substructure (40) flexible, the common electrode that defines the center of a circle with at least three electrodes (142, 144, 146) detection rests on a circumference of the circle and at least a port (54) connecting electrically connected to each sensing electrode and permitting electrical connection to a fetal heart rate monitor; characterized by: the common electrode is separated from the most central sensing electrodes by a distance of between 14 and 20 cm on the concave side of the arch; and the outermost of at least three electrodes (142, 146) detection subtending an arc of about 30 to 45 degrees.