What device is used to electronically measure fetal heart rate information?

The ultrasound transducer is the correct choice for electronically measuring fetal heart rate information. This device uses high-frequency sound waves to create real-time images of the fetus and also picks up the fetal heart sounds transmitted through the fluid of the amniotic sac. By converting these sound waves into electrical signals, the ultrasound transducer can display the fetal heart rate on a monitor, allowing healthcare providers to assess the well-being of the fetus during pregnancy and labor.

While the other devices mentioned can be useful in various medical contexts, they do not specifically serve the purpose of electronically measuring fetal heart rate. An oximeter is used to measure oxygen saturation levels in the blood, a cardiotocograph records contractions and fetal heart rate but relies on a transducer to gather the heart rate data, and a stethoscope can only auscultate heart sounds without providing electronic data or monitoring functionalities.