Fetal Monitors: Understanding the Technology
September 21, 2016 | Evaluations & Guidance
- Fetal monitors, also known as cardiotocographs, measure, display, and record two major parameters: fetal heart rate (FHR) and maternal uterine activity (UA). These can be measured either externally or internally.
a) External monitoring involves placing a pressure transducer (known as a toco transducer) and one or more ultrasound transducers on the mother's abdomen to measure FHR and UA.
b) Internal monitoring involves applying an electrode to the fetal scalp to measure FHR and ECG signals, and using an intrauterine pressure catheter (IUPC) to measure UA and uterine pressure.
Additionally, some fetal monitors include components to monitor certain maternal parameters such as ECG, pulse oximetry (SpO2), noninvasive blood pressure (NIBP), and temperature. All monitors include a built-in printer to obtain graphical trends of FHR and UA.
Additional features of...