What does a fetal scalp electrode measure to determine fetal heart rate?

A fetal scalp electrode measures the electrical activity of the fetal heart by detecting the consecutive R to R wave intervals in the fetal electrocardiogram (ECG). This method provides a precise and continuous measurement of the fetal heart rate, offering detailed insights into how the fetus is responding to various stimuli within the womb. By capturing the R wave, which corresponds to the depolarization of the ventricles in the heart, healthcare providers can accurately assess the fetal heart rate and its patterns over time.

This technique is particularly valuable in situations where external monitoring might not provide sufficient clarity or reliability, such as in the context of maternal obesity or when the fetus is positioned unfavorably. Thus, understanding and evaluating the R to R intervals allows clinicians to monitor fetal well-being effectively.