What term is used to describe how long a contraction lasts in seconds?

The term that describes how long a contraction lasts in seconds is duration. In the context of fetal monitoring, duration refers specifically to the length of time from the beginning of a contraction to its end, measured in seconds. This measurement is essential for evaluating the progress of labor and understanding the pattern of contractions, which can indicate the well-being of the fetus and the effectiveness of uterine contractions during labor.

Other terms like intensity and frequency are related but refer to different characteristics of contractions. Intensity describes how strong the contractions are, while frequency indicates how often the contractions occur within a specific time frame. Amplitude, though not commonly used in this context, generally relates to the height or strength of a wave, which does not apply directly to the measurement of contraction duration. Therefore, duration is the correct term for measuring the length of a contraction.