What is the duration for a gradual deceleration from onset to nadir?

A gradual deceleration in fetal heart rate is characterized by a smooth, gradual decrease in the heart rate that begins at the onset of the deceleration and returns to baseline afterward. The duration of the deceleration from its onset to the lowest point, or nadir, is crucial for classification into different types of decelerations.

A gradual deceleration is typically defined as having a duration of 30 seconds or more from the onset to the nadir. This timeframe is significant in clinical practice because it helps healthcare providers distinguish between transient and more concerning patterns of decelerations. Understanding this pattern allows for appropriate monitoring and intervention based on the fetus's well-being.

In contrast, shorter durations, such as 10 seconds or less, less than 15 seconds, or more than 1 minute, do not align with the established criteria for classifying a deceleration as gradual. Therefore, recognizing that gradual decelerations must last at least 30 seconds aids in interpreting fetal heart rate patterns effectively during surveillance.