Editing Cardiotocography (section)

===Uterine activity===
There are several factors used in assessing uterine activity.  
*'''Frequency:''' the number of contractions per unit time.
*'''Duration:''' the amount of time from the start of a contraction to the end of the same contraction.
*'''Resting tone:''' a measure of how relaxed the uterus is between contractions. With external monitoring, this necessitates the use of palpation to determine relative strength. With an IUPC, this is determined by assessing actual pressures as graphed on the paper.
*'''Interval:''' the amount of time between the end of one contraction to the beginning of the next contraction.

The NICHD nomenclature<ref name=nic/> defines uterine activity by quantifying the number of contractions present in a 10-minute window, averaged over 30 minutes. Uterine activity may be defined as:
*'''Normal:''' 5 or fewer contractions in 10 minutes, averaged over a 30-minute window
*'''[[Uterine tachysystole]]:''' more than 5 contractions in 10 minutes, averaged over a 30-minute window