The majority of obstetric deliveries in the US undergo electronic monitoring and continuous uterine activity and fetal heart rate (FHR) monitoring is the standard of care. Typically, external transducers are employed, the reliability of which depends on their proper positioning, which may be disturbed by patient or fetal movement. The tocodynamometer (strain gauge, toco for short) provides frequency and timing of contractions, but requires transmission of tension from the uterus to the sensor. Fetal heart rate is acquired with an external Doppler ultrasound transducer. The reliability of this monitor depends on the ability to obtain a window to the fetal heart.