electronic fetal monitor (EFM) [Gk, elektron + L, fetus + monere, to warn] , a device that facilitates a more exact measurement of the fetal heart rate and pattern than auscultation of the fetal heart rate with a stethoscope. It also provides an evaluation of the strength of uterine contractions more efficiently than manual palpation. The fetal heart rate and pattern may be monitored externally by an ultrasound transducer or internally by the placement of an electrode directly on the fetal scalp if membranes are ruptured. The strength and pattern of uterine contractions may be monitored externally by the placement of a physical transducer measuring the “hardness” of the uterus or internally with the placement of a catheter that transmits intrauterine pressure to a pressure gauge on the device.
