<p>Systems and methods of monitoring the fetal heart rate in a human subject are described. The subject's umbilicus defines a point on an umbilicus axis length perpendicular to the subject's body. The axis is oriented on an umbilicus plane perpendicular to the subject's length. The system includes at least one sensor mountable in an ellipse defined by the subject's length and width. The width is the umbilicus plane's longest chord. The sensor senses acoustic energy and generates a signal. A processing unit receives the signal to determine average fetal heart rate frequency.</p>
