How are intermittent decelerations defined in fetal heart monitoring?

Intermittent decelerations in fetal heart monitoring are characterized by their occurrence with a lesser frequency in relation to contractions. Specifically, they are defined as those that occur with 50% or fewer contractions within a specified timeframe, typically a 20-minute period. This means that there are instances of fetal heart rate decelerations that correspond to less than half of the uterine contractions occurring during that time, reflecting a transient relationship to contractions rather than a continuous pattern.

This distinction is crucial in fetal surveillance, as it indicates a patterned response to contractions that is not consistently affecting the fetal heart rate. Understanding this concept helps clinicians differentiate between varying types of decelerations and make informed decisions regarding fetal well-being and potential interventions during labor and delivery.