In medicine, cardiotocography (CTG) is a technical means of recording the fetal heartbeat and the uterine contractions during pregnancy, typically in the third trimester.
The machine used to perform the monitoring is called a cardiotocograph, more commonly known as an electronic fetal monitor.
 
Auscultation: In this technique, the nurse or doctor listens to the baby's heart at set intervals during labor. This continuous CTG method is also called electronic fetal monitoring. They will either listen to the heart rate using a fetoscope (putting it on your abdomen), or they will listen by ultrasound (which will amplify the sound of the heartbeat, and be monitored and recorded after a contraction at set times).